Learn how data security standards CMMC 2.0 and ISO 27001 compare in purpose, scope, controls, and processes. Explore our CMMC-ISO 27001 control map, time and cost to implement, and overlap strategies.

How do ISO 27001 and CMMC compare?

ISO 27001 and CMMC 2.0 both strengthen cybersecurity, but they apply differently. ISO 27001 is a global information security standard used throughout industries, while CMMC is a U.S. Department of Defense certification with prescriptive requirements to safeguard Federal Contract Information (FCI) and Controlled Unclassified Information (CUI).

ISO 27001, also known as ISO/IEC 27001:2022, supports the establishment of an Information Security Management System (ISMS) to protect all types of information assets, including digital records, physical files, and intellectual property. 

CMMC 2.0, however, operates with a narrower scope of specific requirements. The standard protects FCI and CUI while exclusively targeting DoD prime contractors and subcontractors.

Beyond scope, the two standards also differ in how you apply controls. ISO 27001 requires you to note information security risks before choosing from among its 93 Annex A controls in the 2022 revision. In contrast, CMMC requires contractors to follow specific practices at each maturity level according to exact written requirements, including aligning with NIST SP 800-171 Rev. 2, and, at Level 3, 24 selected requirements from NIST SP 800-172.

Their certification procedures reflect those aspects. The ISO certification process requires third-party audit activities that are valid for three years, with annual surveillance audits required. The DoD-accredited assessment, however, also grants a three-year certification but requires annual affirmation of compliance and oversight by DoD-accredited bodies.

ISO 27001 vs. CMMC

What do CMMC and ISO 27001 have in common? 

Both CMMC and ISO 27001 aim to establish security protocols to help organizations validate their risk-reducing measures. Their accreditation requires both executive support and appropriate governance systems. A Chief Information Security Officer, Compliance Officer, IT Security Manager, and Procurement Officer are often involved.

The two standards share some common features:

• Both require you to outline the boundaries of your systems, data, and processes.
• Each framework uses risk assessment to guide priorities and resource allocation, aligning with the NIST Cybersecurity Framework (CSF).
• Executive leaders are expected to participate in program development and review processes.
• Both standards include access control and security incident response along with monitoring, vulnerability handling, and continuity planning — typically captured in a Continuous Monitoring Plan (CMP).
• Both extend security awareness requirements to staff, vendors, and supply chain participants, including small and medium-sized businesses (SMBs).
• Each requires change control, documented processes, and secure operational practices supported by audit logs.
• Both rely on ongoing oversight, corrective actions, and recurring external assessments.
  
  

Comparing ISO 27001 and CMMC 2.0

How do CMMC levels relate to ISO 27001?

CMMC levels do not correspond directly to ISO 27001, but there is overlap. ISO 27001 is a single, flexible certification based on risk management, while CMMC progresses through three maturity levels tied to DoD contract requirements. An ISO 27001 foundation can cover many CMMC practices, but not all evidence obligations.

CMMC levels establish progressive security standards, starting from basic FCI protections at Level 1 to advanced CUI protections at Level 3. Every level contains specific implementation requirements that must be followed exactly as stated. ISO 27001 uses a risk-based ISMS framework that provides a single, internationally recognized certification.

Your existing ISO 27001 certification will satisfy many CMMC requirements, especially those at Levels 1 and 2. That said, beginning at Level 2, CMMC requires additional prescriptive evidence and documents such as a CMMC System Security Plan (SSP), a CMMC Plan of Action and Milestones (POA&M), and a Risk Assessment Report (RAR).

For more, see our guides to CMMC Level 2 and CMMC Level 3.

Differences between CMMC and ISO 27001

CMMC is a Department of Defense framework with tiered maturity levels that become mandatory when specified in DoD contracts. ISO 27001 operates independently of regulation, but many customers and industries treat it as a de facto requirement for doing business, especially internationally. 

Differences at a glance:

• CMMC applies to DoD contractors and subcontractors, while ISO 27001, part of the ISO 27000 series, may apply to any organization worldwide.
• CMMC protects FCI and CUI, while ISO 27001 safeguards all information assets.
• CMMC uses prescriptive measures, while ISO 27001 follows a risk-driven, adaptable approach.
• CMMC assessments are conducted by DoD-accredited assessors (C3PAOs for Level 2, DIBCAC for Level 3) on a three-year cycle with annual affirmation. ISO 27001 audits are conducted by independent certification bodies accredited under ANAB/IAF, valid for three years with annual surveillance audits.
• CMMC is mandatory when a DoD contract specifies a level. ISO 27001 is not government-mandated, but is frequently required by customers or industry contracts as a condition of doing business.
  
  

“The biggest differences between these frameworks are the reasons for pursuing them and the doors they open,” says Elliott Harnagel, Product and Compliance Strategist at Strike Graph. “CMMC is mandatory if you are dealing with CUI. There's no getting around the requirements if you work in the defense industrial base. ISO, on the other hand, is optional, and is used to build credibility with your vendors rather than satisfy regulatory requirements.”

Which should you choose? As Harnagel puts it, “When it comes down to it, the frameworks have different goals, so firms should pick the one that more closely aligns with their own compliance objectives.”

CMMC Level 1 vs. ISO 27001

Contrasting CMMC Level 1 and ISO 27001 reveals major differences in their scope and depth, as well as their recognition status. The basic safeguards for FCI at Level 1 do not match the globally recognized risk-based framework for organizational security management provided by ISO 27001.

Differences at a glance:

• Scope: CMMC Level 1 is for FCI; ISO 27001 is for all organizational data.
• Depth: CMMC Level 1 requires 15 FAR 52.204-21 (Federal Acquisition Regulation clause 52.204-21) requirements; ISO covers an entire ISMS with 93 controls in Annex A.
• Approach: CMMC Level 1 is checklist-based; ISO is risk-based and adaptable.
• Certification: CMMC Level 1 uses self-assessment; ISO requires third-party audit and surveillance.
• Recognition: CMMC Level 1 is DoD-specific; ISO 27001 is global.
  
  

In addition to FAR 52.204-21, contractors should also be aware of DFARS 252.204-7012, which mandates the safeguarding of CUI and the reporting of cyber incidents — further reinforcing the need for CMMC Level 2 or higher depending on contract requirements.

CMMC Level 2 vs. ISO 27001 

CMMC Level 2, the most common tier, and ISO 27001 both address information security, but they take different approaches and apply to different scopes. The NIST SP 800-171 requirements for FCI and CUI protection are enforced at Level 2, while ISO 27001 implements a globally recognized risk-based framework that covers a broader scope.

Differences at a glance:

• Scope: CMMC Level 2 protects FCI and CUI; ISO covers all assets.
• Depth: CMMC Level 2 has 110 practices tied to NIST SP 800-171 Rev. 2; ISO uses 93 adaptable Annex A controls.
• Approach: CMMC Level 2 is prescriptive; ISO is flexible and risk-driven.
• Certification: CMMC Level 2 requires either self-assessment (for some contracts) or a third-party accredited audit every three years, with annual affirmation; ISO uses accredited certification bodies and annual surveillance.
• Recognition: CMMC Level 2 is DoD–specific; ISO is global.
  
  

CMMC Level 3 vs. ISO 27001

CMMC Level 3 offers defense-specific advanced protection, while ISO 27001 is an overall standard. Level 3, which applies only to select defense contractors, incorporates 24 additional NIST SP 800-172 requirements on top of Level 2, to protect highly sensitive defense data. ISO 27001 offers a single certification for all organizations.

Differences at a glance:

• Scope: CMMC Level 3 protects highly sensitive defense information; ISO covers all assets.
• Depth: CMMC Level 3 includes Level 2 plus 24 selected requirements from NIST SP 800-172; ISO relies on 93 Annex A controls.
• Approach: CMMC Level 3 is prescriptive and advanced; ISO remains risk-based.
• Certification: CMMC Level 3 requires DoD-accredited DIBCAC (Defense Industrial Base Cybersecurity Assessment Center) assessments; ISO uses independent audits with annual surveillance.
• Recognition: CMMC Level 3 is DoD-specific; ISO is global.

Comparing CMMC Levels vs. ISO 27001

How CMMC and ISO 27001 audits differ

Understanding CMMC and ISO 27001 audit differences is important because each has its own audit structure, evidence requirements, and oversight mechanisms. The ISO certification process requires two stages of assessment with ongoing monitoring, whereas CMMC audits begin with self-assessment and progress through multiple levels including DoD-accredited reviews of specific practices.

CMMC assessments vary by level:

• CMMC Level 1: Annual self-assessment plus executive affirmation. 
• CMMC Level 2: Either self-assessment or a triennial accredited audit, with annual affirmation. Limited POA&Ms are allowed, which must be closed within 180 days. 
• CMMC Level 3: Triennial DoD-conducted assessment, which requires a completed Final Level 2 certification as a prerequisite.
  
  

Key audit differences include:

• ISO 27001 audit structure: Two stages plus annual surveillance.
• ISO evidence: Broad, risk-based, and ISMS-wide (e.g., Statement of Applicability (SoA), internal audits, and management reviews) supporting audit readiness.
• CMMC evidence: Prescriptive “show-me” artifacts for each practice, including configuration records, training records, and audit trail/log entries.
• Oversight: ISO has certification bodies accredited via ANAB/IAF; CMMC has DoD-accredited assessors working with C3PAOs (CMMC Third-Party Assessment Organizations) under Cyber AB (Cyber Accreditation Body, formerly CMMC Accreditation Body).
  
  

How to reuse ISO 27001 controls for CMMC 

The work you have done to obtain ISO 27001 certification provides substantial value for meeting CMMC requirements. The many overlapping areas between frameworks make it easier to map and adapt your ISMS while closing gaps when you start with ISO's structured framework.

Annex A controls in ISO 27001 feature various practices that match CMMC requirements, including access control, security incident response, monitoring and security training. Your risk assessments and documented policies and governance processes from ISO certification can be easily aligned with CMMC prescriptive requirements to reduce duplicate work, and your risk assessment report can be leveraged directly.

That said, CMMC goes further. Indeed, the framework demands more detailed evidence of implementation while adding defense-specific rules for protecting FCI and CUI. Your ISO certification will expedite the process but you will need to customize controls and enhance documentation and undergo a DoD-accredited assessment to achieve CMMC compliance.

According to Harnagel, the greatest advantage ISO 27001-certified organizations have when approaching CMMC is that they already operate with the “machinery” of continuous improvement and control monitoring in place.

“For a company with an existing and functioning ISMS, CMMC compliance should be easier than a firm starting from scratch because the machinery for implementing and continuously complying with a cybersecurity framework is already built,” he says. “Things like tracking nonconformities, having annual internal and external audits, and having compliance responsibility specifically assigned are all things that will be extremely valuable when adding in CMMC requirements.”

Michael Greenman, Senior Manager of Cloud Solutions at Deltek, emphasizes that mapping each control to proof is where ISO-certified firms may fall short.

“So, bottom-lining it, ISO can speed up CMMC preparation by showing strong, foundational processes and procedures. But those contractors seeking CMMC certification will still need to map all the required controls and implemented security procedures directly to the NIST SP 800-171 controls by implementing DoD-specific requirements.”

How to reuse CMMC controls for ISO 27001

Organizations that already comply with CMMC standards can leverage most of their existing work to achieve ISO 27001 certification. The structured controls of CMMC provide a solid foundation for building an ISO-ready ISMS since both frameworks share many of the same practices.

The CMMC framework demands specific practices for access control and security incident response, plus employee training, monitoring, and awareness. The ISO 27001 Annex A controls map closely to these same requirements. CMMC’s detailed documentation requirements align with ISO's need for verifiable records. 

Their operational methods are distinct, however. The risk-based framework required by ISO 27001 emphasizes continuous improvement, whereas CMMC relies on prescriptive requirements. Your CMMC foundation requires additional elements such as risk assessments, governance reviews, and management oversight to achieve ISO 27001 certification – but much of the existing CMMC work can reduce the time and cost of achieving ISO certification once these requirements are addressed.

Greenman says that CMMC Level 2 documentation can likely be carried straight into ISO with only a few additional areas, like governance and improvement processes, left to expand upon.

“ISO 27001 Annex A controls are broader and more flexible, but much of the technical and procedural groundwork is already in place,” he says. “CMMC requires documented policies, procedures, and evidence of implementation. And that documentation can most certainly be repurposed, almost directly, into the ISMS framework for ISO 27001.”

What’s the difference between CMMC and ISO 27001 evidence?

CMMC evidence requires proof that all required practices operate exactly as recorded in the published requirements. In contrast, the evidence required for ISO 27001 demonstrates how your risk-based ISMS operates effectively through comprehensive documentation, structured governance, and ongoing continuous improvement processes.

CMMC evidence requires strict adherence to specific requirements. Your organization must show evidence of following particular practices, including system configurations, access logs, training records, and procedure execution consistency. The assessment process indeed requires direct evidence that matches the control requirements, often including audit trail/log artifacts.

ISO 27001 evidence takes a broader perspective. The evidence base for ISO 27001 includes risk assessments alongside policies, management review minutes, audit reports, and continuous improvement records. The ISMS must demonstrate its effectiveness through monitoring mechanisms and records of continuous improvement according to ISO 27001 standards, including the Statement of Applicability (SoA).

CMMC evidence requires documentation of specific practices tied directly to contractual obligations. ISO 27001 evidence, by contrast, focuses on demonstrating a functioning risk-based management system and organizational maturity.

Full mapping of ISO 27001 to CMMC levels

This crosswalk mapping of ISO 27001 Annex A controls to CMMC Levels 1–3 highlights overlaps, reduces duplicate work, and gives organizations a clear reference for planning compliance.

Download the complete CMMC vs ISO 27001 control mappings here. 

Time and cost to achieve ISO 27001 and CMMC compliance

Organizations must dedicate 9 months or more to ISO 27001 certification, which typically starts around $50,000 and can run into six figures depending on scope. CMMC Level 2 time and costs are likely to be in the same general range, with larger organizations taking more time and money.

ISO 27001 certification for small organizations typically takes 9–12 months. More time is needed when dealing with large, complex environments. The costs of ISO 27001 certification result from audit expenses, consulting services, and remediation work. The expenses for readiness reviews, documentation, staff training, technology or process changes, and audit fees should be included in your certification expenses.

When basic safeguards are already established, organizations can obtain CMMC Level 1 certification more quickly. However, Level 2 of the framework demands more effort and resources and requires 6-12 months or more to complete at increased costs. The process requires organizations to close NIST 800-171 gaps, implement monitoring systems, and create detailed evidence for an accredited assessment.

Both frameworks require organizations to make continuous financial investments. The standard ISO demands yearly surveillance audits for ongoing certification. The CMMC framework requires reassessments through affirmations which depend on the level of certification. Your organization should budget for both recurring expenses and sustained compliance throughout the three-year certification duration and consider reciprocity opportunities or a bundled certification approach (e.g., ISO 27001 plus FedRAMP plus CMMC) where appropriate.

In addition to the financial burden, organizations face limited assessor availability, Greenman says. 

“DoD’s latest estimate is that over 130,000 entities are expected to need a CMMC Level 2 certification, and the counter stat to that is, as of early October 2025, there are just over 80 total certified third-party assessment organizations to service those needs.”

Time and cost to get an ISO 27001 certification

ISO 27001 certification requires significant time and financial resources. The time ranges from 9 to 12 months for most firms, though larger or more complex organizations can take up to 18 months. Experienced teams may move faster. Both internal work and external audit fees factor in.

The preparation process for most organizations is part of the 9–12 month overall timeline. Preparation often takes 6 to 9 months and involves gap assessments, creating policies, risk analysis, staff training, and evidence collection. Organizations with extensive regulatory needs or complex structures may need more time.

The costs for this process generally start around $50,000 and can run into six figures depending on scope. External certification audits usually cost $10,000 to $20,000, with required surveillance audits in years 2 and 3 typically ranging from $8,000 to $15,000. Additional expenses can include consulting support, remediation, tool purchases, and staff time.

“For ISO we usually see firms take 9 months to a year to put together a solid program, and then 3 months to arrange and have the external audit performed,” Harnagel says. “This can be sped up; 6 months is possible if a team has prior compliance experience and identifies an auditor early.” 

He adds that the cost of the certification audit varies, as does the quality of the assessors. “It's possible to get an ISO external assessment that utilizes offshore resources for as low as $5k. Assessments from more established firms generally start at $10-15k and go up from there.” 

Time and cost to get ISO 27001 if you already have a CMMC certification

Obtaining ISO 27001 certification following CMMC certification at any level takes less time and is less expensive, especially when you already hold CMMC Level 2 certification. Organizations can often complete the process in 2 to 6 months, with additional costs typically ranging from $10,000 to $50,000.

The core work involves incorporating elements that CMMC does not require. These include, for example, a formal risk methodology alongside a Statement of Applicability (SoA), as well as an internal audit program, regular management reviews, and continuous improvement tracking. The costs mostly cover readiness support (if you decide to have it), documentation refinement, and the expenses for Stage 1 and Stage 2 certification audits. Remediation requirements are less intense since the policies, logging system, training programs, and access controls from CMMC can be reused.

Time and cost to get a CMMC certification

The time needed for CMMC certification varies based on the specific certification level. The path to Level 1 certification is fast and inexpensive, but Level 2 demands extensive time and financial investment. Most organizations should allocate at least 6 to 12 months, with costs typically ranging from $50,000 upward depending on size, scope, and remediation needs.

Organizations with basic cybersecurity practices already in place can expect to achieve Level 1 certification within a few months. The expenses mainly include documentation of safeguards and the completion of the mandatory assessment.

Level 2 is more demanding, however. The process to close NIST SP 800-171 gaps and implement formalized policies and technical protections like MFA (Multi-Factor Authentication) and logging, alongside creating assessment-ready evidence, will require at least 6 to 12 months. Expenses are higher when you need to perform remediation work, which might include tool upgrades, improved access control systems, or enhanced monitoring capabilities. 

Harnagel said to expect a minimum of one year to ensure compliance with all 110 controls. “As for costs,” he adds, “CMMC external Level 2 audits start at around $35k for smaller firms and go up from there.” 

Time and cost to get CMMC if you already have ISO 27001

Obtaining CMMC certification, especially Level 2, is faster and less expensive for organizations that already have ISO 27001 certification. Most organizations require 3 to 9 months to complete the process, which usually costs $10,000 to $50,000, depending on the remaining gaps.

Your primary task in this transition becomes meeting CMMC's specific requirements which differ from those of building a full ISMS from the ground up. Your task includes bringing NIST SP 800-171 practices into alignment and implementing stronger technical safeguards through MFA across systems, all the while developing deeper logging and alerting capabilities and establishing configuration baselines. You will also need to create additional defense-specific documents in the form of a System Security Plan (SSP) and Plan of Action and Milestones (POA&M).

To confirm your FCI/CUI scope, you should prepare evidence that matches CMMC's requirements and schedule a DoD-accredited assessment for Level 2. (Costs will be higher if you need tool upgrades, endpoint coverage extension, and SIEM (Security Information and Event Management) configuration modifications.) In most cases, your existing ISO documentation alongside your training and governance framework can be applied with minimal modifications.

How to implement CMMC and ISO 27001 efficiently

The joint implementation of CMMC and ISO 27001 standards can lessen time and cost significantly. The frameworks share many common controls, enabling you to create a unified compliance program that eliminates duplication and streamlines documentation for both standards.

A strategic starting point is to perform a combined gap analysis that compares ISO 27001 Annex A controls with CMMC practices to identify overlap. The next step involves creating standardized policies and storing evidence in a single location, which decreases staff work and minimizes audit fatigue.

Using modern compliance platforms can further streamline the implementation process by automating control mapping, evidence collection, and real-time gap identification. These tools reduce reliance on spreadsheets, speed audit readiness, and allow your team to focus on risk management rather than manual documentation.

“There is a large amount of overlap in control requirements between ISO and CMMC, so pursuing them both together can save time if a firm wants to achieve compliance with both frameworks,” Harnagel says. “The biggest hurdle when pursuing multiple frameworks is keeping documentation and audit evidence organized and mapped back to each framework appropriately. Using a software like Strike Graph can help with that, as you can combine your control and evidence lists into one platform.”

He adds that both frameworks also require a process of addressing and remediating control deficiencies. “ISO requires firms to maintain Nonconformity and Corrective Action plans, and CMMC requires Plans of Action and Milestones. Strike Graph's “Action Items” feature allows firms to maintain one list of control remediation efforts so that nonconformities and POA&Ms can be consolidated to a single list.”

Developing a unified compliance roadmap that includes timelines, documentation milestones, and audit targets for both frameworks can further streamline efforts and ensure long-term certification success. And as federal cybersecurity expectations continue to evolve in response to a changing security landscape, frameworks like CMMC are becoming increasingly central to contract readiness and risk management.

Streamline CMMC and ISO 27001 compliance with Strike Graph 

Running two compliance programs in parallel doesn’t have to double your work. Strike Graph gives you a single platform for CMMC and ISO 27001 to map controls, track evidence, and manage audits across both frameworks, helping you cut duplication and stay compliant with less effort.

Strike Graph’s AI-powered compliance management platform consolidates tasks such as control ownership, nonconformities, System Security Plans (SSPs) and Plans of Action and Milestones (POA&Ms) into a single workflow. Instead of juggling spreadsheets or separate systems, you can manage documentation and audit readiness in one place.

With policy templates, procedure guides, and partnerships with accredited auditors, Strike Graph helps you move faster from preparation to certification. Whether you’re adding CMMC to an existing ISO program or pursuing both together, we make it easier to save time, reduce costs, and stay audit-ready.

Schedule a Strike Graph demo today.

FAQs on CMMC 2.0 vs. ISO 27001

How are CMMC 2.0 and ISO 27001 related to NIST?

CMMC 2.0 mainly draws its controls from NIST SP 800-171, but ISO 27001 follows a risk-based approach matching ISMS standards. CMMC utilizes NIST guidance in a prescriptive way, while ISO 27001 uses it contextually through the selection of Annex A controls.

Does having NIST SP 800-171 compliance mean I already meet ISO 27001?

No. The requirements of 800-171 control standards are addressed, but ISO 27001 demands an ISMS that uses a risk-based methodology while requiring Statement of Applicability (SoA), internal audits, management reviews, continuous improvement and certification by an accredited body.

Can ISO 27001 certification replace CMMC compliance?

No. The certification of ISO 27001 does not replace the CMMC requirements. Defense contracts require CMMC levels as enforceable conditions of award and performance. Being ready for ISO 27001 does not mean you can skip fulfilling CMMC prescriptive requirements or undergoing DoD-accredited assessment when necessary.

Which should I do first — ISO 27001 or CMMC?

Businesses that require defense contracts in the near future should start by prioritizing CMMC. Organizations should begin with ISO 27001 certification when seeking global recognition through a security management framework that they can use across different areas – however, organizations that are aiming for the simultaneous implementation of both frameworks can strategically minimize overlapping efforts.

Should I pursue ISO 27001 or CMMC if I’m short on time or budget?

The right choice depends on your business goals. Organizations need CMMC certification when their contracts require it. That said, the market scalability and global value of ISO 27001 can outweigh that of CMMC compliance when no contracts require CMMC compliance. Organizations can, however, combine their efforts to pursue both and achieve the best possible total cost reduction.

Can I limit the scope of my ISO 27001 or CMMC audit?

Yes — scoping is allowed and essential. The audit requires organizations to specify exactly which systems and their related processes and data boundaries should be included in the assessment. Scopes need to be defensible since omitting essential assets or data could result in nonconformities. The certification scope needs to be defined exactly to establish boundaries that auditors and assessors will accept.

How much of my ISO 27001 evidence can I reuse for CMMC?

Most evidence from your ISO 27001 framework, including policies and procedures, along with training materials, risk records, and control artifacts, can be reused in the CMMC framework. You will need to develop new documents for SSP (System Security Plan) and POA&M (Plan of Action and Milestones) and collect more detailed evidence that meets the specific requirements of NIST SP 800-171.

What happens if I fail a CMMC or ISO 27001 audit?

The audit process results in nonconformities and deficiencies. You need to develop a corrective action plan to address nonconformities and provide evidence within the agreed timelines. The certification process or contract eligibility can proceed once all issues are resolved to the satisfaction of the audit team.