How VA Disability Ratings Work: The Combined Ratings Formula Explained

When a veteran has more than one service-connected disability, the VA does not simply add the individual ratings together. Instead, it uses a method called the whole person theory, codified in Title 38 of the Code of Federal Regulations, Section 4.25 (38 CFR § 4.25). Understanding this formula is essential for veterans to accurately estimate their combined rating and monthly compensation.

The Whole Person Theory (38 CFR § 4.25)

The VA treats a person as 100% efficient — a whole person — before any disabilities are applied. Each disability reduces the remaining efficiency, not the original 100%. The formula works as follows:

1. Sort all disabilities from highest to lowest rating.
2. Apply the highest-rated disability first: the combined value equals that rating percentage.
3. For each subsequent disability, calculate the remaining efficiency (100 minus the current combined value), then multiply that remaining efficiency by the next disability rating, and add the result to the combined value.
4. After all disabilities are combined, round the final value to the nearest whole number divisible by 10. Values ending in 5 are rounded up.

Worked Example

A veteran has three service-connected disabilities rated at 70%, 30%, and 10%. The VA processes them in descending order:

• Step 1: 70% disability applied. Combined = 70%. Remaining efficiency = 30%.
• Step 2: 30% disability applied to remaining 30%. Contribution = 30% × 30% = 9%. Combined = 70% + 9% = 79%. Remaining efficiency = 21%.
• Step 3: 10% disability applied to remaining 21%. Contribution = 21% × 10% = 2.1%. Combined = 79% + 2.1% = 81.1%.
• Rounding: 81.1% rounds to 80% (nearest 10; the digit in the ones place is 1, which is below 5).

The final combined rating is 80%, not 110% (which simple addition would incorrectly suggest). This is why veterans with multiple disabilities are often surprised that their combined rating is lower than expected.

Why the VA Uses This Method

The VA's rationale, as stated in the regulatory history of 38 CFR § 4.25, is that a person cannot be more than 100% disabled. Each subsequent disability can only affect the portion of the person that remains functional after accounting for prior disabilities. This prevents the mathematical impossibility of a combined rating exceeding 100% through simple addition.

The Bilateral Factor (38 CFR § 4.26)

If a veteran has disabilities affecting paired extremities — both arms, both legs, or one arm and one leg — the VA applies a bilateral factor before combining those ratings with other disabilities. The bilateral factor adds 10% of the combined value of the bilateral disabilities before that combined value is folded into the overall calculation. This adjustment recognizes that disabilities affecting both sides of the body create a greater functional impairment than the standard formula would reflect.

2025 Monthly Compensation Rates

VA disability compensation rates are adjusted annually based on the Social Security Administration's cost-of-living adjustment (COLA). The 2025 rates (effective December 1, 2024) for a veteran with no dependents are as follows:

Source: VA.gov — 2025 VA Disability Compensation Rates (effective December 1, 2024, per 38 U.S.C. § 1114). Rates are higher for veterans with dependents (spouse, children, or dependent parents). Veterans rated at 30% or higher receive additional compensation for each qualifying dependent.

Total Disability Individual Unemployability (TDIU)

A veteran who cannot maintain substantially gainful employment due to service-connected disabilities may qualify for Total Disability Individual Unemployability (TDIU), which pays at the 100% rate even if the combined rating is below 100%. The general eligibility threshold is a single disability rated at 60% or higher, or two or more disabilities with a combined rating of 70% or higher where at least one disability is rated at 40% or higher. Source: 38 CFR § 4.16.

How to Apply for a VA Disability Rating

Veterans can file a claim for disability compensation through VA.gov, by mail, or in person at a VA regional office. Working with an accredited Veterans Service Organization (VSO) — such as the American Legion, VFW, DAV, or AMVETS — is free of charge and can significantly improve the accuracy and completeness of a claim. VSO representatives are accredited by the VA under 38 CFR § 14.628.