FAR and DFARS: What Federal Contractors Must Know

DFARS does not replace the FAR.

For a DoD pursuit, contractors usually need to read the FAR, the related DFARS coverage, applicable DoD or component rules, current deviations, and the actual solicitation or contract.

The practical question is not “FAR or DFARS?” It is “Which layers apply to this acquisition?”

01What Is the Difference Between FAR and DFARS?

The FAR is the primary document in the Federal Acquisition Regulations System. It provides uniform acquisition policies and procedures across executive agencies. Agencies may issue their own acquisition regulations to implement or supplement the FAR. See FAR Part 1.

DFARS is DoD’s acquisition regulation supplement.

DFARS 201.301 says the supplement contains DoD-wide policies, requirements of law, delegations of FAR authorities, authorized deviations, and policies that can materially affect contractors or offerors.

The basic comparison is:

The official DFARS is codified in Title 48, Chapter 2. DFARS 201.303 also requires its numbering to parallel the FAR wherever practical.

02How FAR and DFARS Work Together

Think of DFARS as a defense layer added to the federal baseline.

If the FAR already addresses a subject, DFARS may:

• implement the FAR rule for DoD;
• add a DoD-specific requirement;
• delegate an authority;
• provide an authorized deviation; or
• add coverage for a defense-specific issue.

DFARS 201.301 expressly describes this implementation and supplementation role.

This means a contractor should not read DFARS in isolation.

If you find DFARS Part 225, for example, the related federal subject is FAR Part 25. If you find DFARS Part 219, start with FAR Part 19 and then read the defense-specific coverage.

Read the base rule and the defense layer together.

03The FAR–DFARS Regulatory Stack

For a DoD pursuit, use this research stack.

Do not treat this as a simple ranking where the bottom source always overrides the top.

Applicability depends on the regulation, deviation, solicitation, and acquisition.

The value of the stack is that it prevents a common research mistake: finding one rule and assuming the research is finished.

04How FAR and DFARS Numbering Connects

The numbering relationship is designed to help users move between the two systems.

DFARS 201.303 explains that DFARS implementation generally follows the matching FAR number. Supplemental material can use numbers of 70 and above.

For example:

A supplemental DFARS section may also use a -70 number.

For example, DFARS 201.303 shows how a FAR section such as 19.501 can correspond to DFARS 219.501, while supplemental coverage can appear as 219.501-70.

Military departments and DoD components may issue another supplement below DFARS. DFARS requires those supplements to parallel FAR and DFARS numbering, using supplemental numbers of 90 and above when needed.

That numbering pattern can save research time.

05What Does DFARS Add That FAR Does Not?

At the comparison level, the answer is simple:

DFARS addresses DoD-specific acquisition needs that the governmentwide FAR does not fully resolve.

The official DFARS says its content can include:

• requirements of law;
• DoD-wide policies;
• delegated FAR authorities;
• deviations from FAR requirements; and
• policies with a significant contractor or offeror impact.

In practice, defense-specific coverage can touch areas such as:

• information and cybersecurity;
• sourcing and foreign acquisition;
• technical data and intellectual property;
• contractor qualifications;
• contract administration;
• commercial acquisition;
• subcontracting;
• supply-chain matters; and
• defense-specific clauses.

This article stops at the comparison layer.

The detailed question—what DFARS obligations does a defense contractor need to satisfy?—belongs on a dedicated DFARS compliance page.

06What Is DFARS PGI?

DFARS also has Procedures, Guidance, and Information (PGI).

DFARS 201.301 says DoD procedures, guidance, and information that do not meet the criteria for inclusion in DFARS are issued in PGI instead. The current official PGI compilation is published alongside DFARS on Acquisition.gov.

That creates an important distinction:

DFARS text and DFARS PGI are not the same thing.

PGI can explain how DoD personnel implement a rule or process.

For contractor analysis, use PGI as context where relevant. Then return to the actual solicitation, contract provision, clause, regulation, or deviation that controls your action.

07When Does DFARS Apply?

For a DoD acquisition, the FAR and DFARS generally work together.

DFARS 201.104 expressly states that FAR and DFARS apply to purchases and contracts by DoD contracting activities supporting foreign military sales or NATO cooperative projects as well, unless DFARS says otherwise.

For a civilian-agency acquisition, your regulatory stack normally begins with the FAR and that agency’s own acquisition supplement rather than DFARS.

For a DoD subcontractor, the analysis becomes more specific.

Do not assume the entire DFARS automatically applies to every subcontract merely because the end customer is DoD. Review the subcontract and the provisions or clauses that must flow down or otherwise apply.

That is a clause-level compliance job, not a FAR-versus-DFARS comparison job.

08What Do “FAR DFARS” and “FAR DFAR” Mean?

Searches for FAR DFARS usually refer to the relationship between the two regulatory systems.

You may also see FAR DFAR used informally.

The official name is DFARS, with an “S,” because it is the Defense Federal Acquisition Regulation Supplement.

Likewise, the phrase FAR DFAR regulations is often used informally to ask how federal and defense acquisition rules interact.

The practical answer remains the same:

FAR is the governmentwide baseline. DFARS adds the DoD acquisition layer.

09How to Evaluate FAR DFAR Requirements on a Live Bid

A search for FAR DFAR requirements usually hides a better contractor question:

Use this sequence.

1. Identify the Customer

Is the buyer a civilian agency or DoD?

If it is DoD, plan to review both FAR and DFARS coverage.

2. Capture the Exact Citation

Do not write “DFARS cybersecurity” or “FAR pricing” in your review notes.

Capture the actual:

• FAR citation;
• DFARS citation;
• clause or provision;
• clause date; and
• solicitation section.

3. Read the FAR Counterpart

Establish the federal baseline first.

Use the Federal Acquisition Regulation hub for the broader research method.

4. Read the Related DFARS Coverage

Ask what the defense supplement implements, adds, or changes.

5. Check the Component Layer

A military department or defense component may have its own supplement.

DFARS 201.304 expressly permits departments, agencies, and component organizations to issue acquisition regulations that implement or supplement FAR or DFARS.

6. Check Current Deviations

This step matters more in 2026 because the regulatory environment is changing.

DoD maintains a current page for Revolutionary FAR Overhaul class deviations. The page includes revised DFARS parts, related PGI, and numerous DoD RFO class deviations. See DoD DPCAP — DFARS Revolutionary FAR Overhaul Class Deviations.

7. Return to the Solicitation

Ask:

• What text is actually included?
• What is incorporated by reference?
• Has an amendment changed it?
• What must the offeror do now?
• What becomes a post-award obligation?

If the issue becomes a must-meet proposal condition, move it into the RFP requirements workflow.

10FAR and DFARS Are Both Changing in 2026

Because this is a living comparison page, current status matters.

As of August 30, 2026:

• Acquisition.gov displays the codified FAR as FAC 2026-01, effective March 13, 2026.
• The official DFARS compilation displays DFARS Change 5/7/2026, effective May 7, 2026.
• DoD also maintains separate FAR-overhaul class deviations, including revisions issued after that DFARS compilation date.

That last point is important.

The current published DFARS compilation is not always the only source you need for a live DoD acquisition.

Current deviations can affect the analysis.

If the change itself becomes the question, use the FAR overhaul tracker rather than expanding this page into a change log.

11Five FAR vs. DFARS Mistakes to Avoid

1. Assuming DFARS Replaces FAR

It supplements and implements FAR for DoD.

Read both.

2. Reading Only the DFARS Section

Find the related FAR coverage first.

The numbering system was built to support that cross-reference.

3. Treating PGI Like a Contract Clause

PGI provides DoD procedures, guidance, and information.

Verify what the actual contract or solicitation requires.

4. Ignoring Component Supplements and Deviations

DoD is not one regulatory document.

The military department or component and current deviations can matter.

5. Using an Old Compliance Summary

Both FAR and DoD’s acquisition framework are changing.

Check the current official text before making a bid or performance decision.

12What Contractors Should Do Next

The difference between FAR and DFARS is easy to state but more useful to apply.

FAR establishes the federal acquisition baseline. DFARS implements and supplements that baseline for DoD. A live defense acquisition may also require a component supplement, current deviation, PGI context, and specific solicitation or contract language.

For every important regulatory question, trace the full stack before turning it into a contractor action.

Use the Federal Acquisition Regulation hub when you need the broad FAR framework. Use the FAR overhaul tracker when current deviations or regulatory changes are the issue.

Do not choose between FAR and DFARS. Determine how they work together on the acquisition in front of you.

13Sources & Official References

1. 01Acquisition.gov — Federal Acquisition Regulation
2. 02Acquisition.gov — FAR Part 1, Federal Acquisition Regulations System
3. 03Acquisition.gov — FAR 1.301, Agency Acquisition Regulations
4. 04Acquisition.gov — DFARS
5. 05Acquisition.gov — DFARS 201.301, Policy
6. 06Acquisition.gov — DFARS 201.303, Publication and Codification
7. 07Acquisition.gov — DFARS PGI
8. 08DoD DPCAP — DFARS Revolutionary FAR Overhaul Class Deviations