How VA Combined Disability Rating Works (38 CFR 4.25): The 2026 Plain-English Guide

Published 2026-05-20 · Reference, not legal advice · Source: 38 CFR 4.25 + VA.gov compensation rates

TL;DR. Two ratings of 50% each don't equal 100% — they equal 75% (rounded to 80%). The VA combines ratings using a "remaining function" formula in 38 CFR 4.25, then rounds the final answer to the nearest 10. Higher ratings are combined first. Bilateral conditions get a 10% bonus on the combined value of the pair. Dependents add to the dollar amount only at 30% and above. None of this is intuitive, which is why most veterans miscalculate by a wide margin the first time.

The VA combined rating is the single most misunderstood number in the disability compensation system. Veterans add their ratings on paper, see a much larger total than what shows up in their decision letter, and conclude the VA shorted them. The shortfall is real but it is not error — it is the way 38 CFR 4.25 has worked since 1945. This guide walks through the formula in plain English, then runs three worked examples and answers the six questions that come up most often.

If you want the answer for your specific ratings before you finish reading, use the free combined rating calculator on the home page. It implements the formula below and shows the math step by step.

Why ratings aren't additive

Start with the system the VA is trying to express. A 100% disability rating represents total functional impairment — the veteran is regarded as unable to follow substantially gainful employment because of service-connected conditions alone. A 50% rating represents half of that loss. A 10% rating represents one-tenth.

If two 50% ratings added to 100%, every veteran with two moderately disabling conditions would be totally disabled on paper. A veteran with knee arthritis at 30% and hearing loss at 30% would land at 60% by simple addition. A veteran with five conditions rated 20% each would be at 100%. The system would collapse into nonsense within weeks of taking effect.

To prevent that collapse, the VA frames each rating as a percentage of the function the veteran still has after prior ratings are applied — not as a percentage of an unchanging 100% baseline. The first rating reduces the veteran's function from 100% to (100 − R1)%. The second rating then applies to that remaining function. The third rating applies to what is still left after the second, and so on. The formula is:

combined = R1 + R2 × (1 − R1/100)

R1 is the highest existing rating (or the running total from the previous step). R2 is the next rating to be combined. R2 only operates on the (100 − R1) percent the veteran still has left.

The math in three lines

Three rules, applied in order, will reproduce the VA's combined-ratings-table result for any reasonable number of ratings:

  1. Sort the ratings from highest to lowest. The combined rating is the same regardless of the order you list conditions in, but sorting high-to-low matches the intuition that the "biggest" impairment is the anchor.
  2. Combine each rating against the function left after the prior step. Start with the highest rating as the running total. For each subsequent rating, add the next rating multiplied by the remaining function (1 − running/100). Keep a running total to two decimal places.
  3. Round to the nearest 10. Under 38 CFR 4.25(a), the final combined value must be expressed as a multiple of 10. A combined raw value of 74 becomes 70. A combined raw value of 75 becomes 80.

The official "combined ratings table" published in 38 CFR 4.25 is just a lookup table that pre-computes the result of the formula for every pair of ratings. The VA Rating Specialist uses the table; the formula and the table produce identical results.

Worked example 1: two ratings (the simple case)

Veteran with PTSD 50% and lumbar strain 30%.

  1. Sort high-to-low: 50, 30. Running total starts at 50.
  2. Combine 30 against remaining function (100 − 50) = 50%. Addition = 30 × 0.50 = 15. New running total = 50 + 15 = 65.
  3. Round 65 to the nearest 10 → the rule rounds .5 up, so 65 → 70%.

Combined rating: 70%. Not 80% (additive).

Worked example 2: three ratings

Veteran with PTSD 50%, sleep apnea 30%, and tinnitus 10%.

  1. Sort high-to-low: 50, 30, 10. Running total starts at 50.
  2. Combine 30 against (100 − 50) = 50%. Addition = 30 × 0.50 = 15. Running total = 65.
  3. Combine 10 against (100 − 65) = 35%. Addition = 10 × 0.35 = 3.5. Running total = 68.5.
  4. Round 68.5 to the nearest 10 → 70%.

Combined rating: 70%. The tinnitus added only 3.5 points to the running total, not 10. This is normal — the smaller the remaining function, the smaller the additional contribution of each new rating.

That last observation is the practical insight. Once a veteran's combined rating reaches the 70–90 range, additional service-connected conditions of 10% or 20% contribute very little to the combined value. A 10% rating combined against 30% remaining function contributes 3 points. A 10% rating combined against 10% remaining function contributes 1 point. This is sometimes called the "rule of diminishing returns" in VA-claim circles. It is not a separate rule — it is just the geometry of the combining formula.

Worked example 3: five ratings, the diminishing-returns case

Veteran with PTSD 70%, lumbar strain 40%, knee strain 20%, hearing loss 10%, tinnitus 10%.

  1. Sort: 70, 40, 20, 10, 10. Running total starts at 70.
  2. Combine 40 against 30% remaining. Addition = 40 × 0.30 = 12. Running total = 82.
  3. Combine 20 against 18% remaining. Addition = 20 × 0.18 = 3.6. Running total = 85.6.
  4. Combine 10 against 14.4% remaining. Addition = 10 × 0.144 = 1.44. Running total = 87.04.
  5. Combine 10 against 12.96% remaining. Addition = 10 × 0.1296 = 1.3. Running total = 88.34.
  6. Round 88.34 to the nearest 10 → 90%.

Combined rating: 90%. The last three ratings together added only about 6 points to the running total — they would have added 40 if the math were additive.

Run your own ratings through the calculator →

The rounding rule (38 CFR 4.25(a))

The final combined rating must be expressed as a multiple of 10. This is not a courtesy — it is required by regulation because the published monthly compensation tables only contain dollar figures at the 10/20/30/40/50/60/70/80/90/100 brackets.

Rounding follows the standard arithmetic rule. Anything below the midpoint rounds down; anything at the midpoint or above rounds up. A combined raw value of:

The half-point of $5K–$10K of annual compensation that often hangs on a single rounding decision is part of why veterans appeal denials of additional ratings. A 10% increase in a single condition's rating can sometimes push the combined raw value from 74 to 75, jumping the rounded result from 70% to 80% — and the monthly compensation from the 70% bracket ($1,716 in 2026) to the 80% bracket ($1,995). On an annual basis that is roughly $3,350 of additional compensation.

The bilateral factor (38 CFR 4.26)

The bilateral factor is the most commonly overlooked piece of the combined rating system. When service-connected disabilities affect both arms, both legs, or paired skeletal muscles on opposite sides of the body, the VA first combines those paired ratings using the standard 38 CFR 4.25 formula, then adds 10% of the combined value back to the combined value, and then combines that increased value with any remaining non-paired ratings.

Three things to know about it:

The calculator on the home page does not currently model the bilateral factor; a future version will. If you have paired-extremity conditions, calculate the pair manually first (combine, then add 10%), then enter that single combined number alongside any non-paired ratings.

Dependents and the 30% threshold

The combined rating and the monthly compensation amount are two different things. The combined rating is a percentage. The monthly compensation is a dollar figure looked up from VA tables that depend on the rating and the veteran's dependents.

At 10% and 20% combined, the VA pays a single flat amount regardless of marital status or children. This is set by 38 CFR 3.4(b)(1) and is independent of any dependent the veteran actually has.

At 30% combined and above, the VA publishes a "with dependents" rate table that adds fixed amounts for:

The dependent-add-on amount scales with the combined rating. A spouse adds roughly $64/month at 30% and roughly $212/month at 100% in 2026. For a worked-out 2026 number for your specific situation, the calculator shows the monthly figure once you tick the spouse box and enter the dependent counts.

Two veterans at 70% who get different amounts of money

The schedular combined rating sets the base monthly compensation, but there are three named overlays that can change the final paid amount without changing the combined percentage on the decision letter:

TDIU (Total Disability based on Individual Unemployability)

Under 38 CFR 4.16, a veteran with a combined rating of 70% (or 60% with a single rating of 60% or above) who cannot follow substantially gainful employment because of service-connected conditions can receive compensation at the 100% rate even though the schedular combined rating remains at 70%. The schedular rating on the decision letter does not change. The monthly check matches the 100% bracket. TDIU is requested on VA Form 21-8940 and requires evidence from the veteran and from each employer in the last five years.

Special Monthly Compensation (SMC)

Under 38 USC 1114, veterans with certain severe service-connected conditions (loss of use of a hand or foot, blindness in one or both eyes, the need for aid and attendance, housebound status, etc.) receive an additional flat monthly amount on top of the schedular rate. SMC categories are lettered (SMC-K, SMC-L, SMC-M, SMC-N, SMC-O, SMC-S, SMC-T, etc.) and stack in defined combinations.

Paragraph 29 / 30 / 31 entitlements

These are temporary 100% ratings during the convalescence period after a service-connected surgery (38 CFR 4.30) or a hospital stay over 21 days for a service-connected condition (38 CFR 4.29). They are not part of the schedular combined rating but they replace the schedular rate during the entitlement period.

The takeaway: a "70% veteran" can be paid at the 70% rate, the 100% rate (via TDIU), or somewhere in between with SMC stacked on top. The combined rating in 38 CFR 4.25 sets only the base.

Common mistakes when self-calculating

Five errors come up over and over when a veteran tries to predict the combined rating in advance of a decision:

  1. Adding instead of combining. The most common error and the one that produces the largest gap between expectation and decision letter. Two 50s is 75% raw, 80% rounded — not 100%.
  2. Forgetting the rounding step. A combined raw value of 88.34% feels like 88% but appears as 90% on the decision letter, which can pay several hundred dollars more per month.
  3. Trying to combine pre-rounded numbers from a prior decision. If a veteran already has a combined 70% from prior conditions and is being granted a new 30% rating, the combination is not 70% combined with 30%. The Rating Specialist re-combines the individual unrounded ratings from scratch. Use the raw ratings, not the prior rounded combined.
  4. Ignoring bilateral. Veterans with paired-extremity ratings often underestimate by 5–15% by skipping the 38 CFR 4.26 step.
  5. Confusing the rating with the dollar amount. The combined rating is a percentage. The check is a dollar figure that depends on the percentage and dependents and any TDIU or SMC entitlements. A 70% TDIU veteran with a spouse and three children in 2026 receives roughly $4,500/month even though the rating decision says "70%".

Putting it all together

The order of operations a Rating Specialist actually follows on a multi-condition decision is approximately:

  1. Assign individual percentages for each service-connected condition under the appropriate diagnostic code in 38 CFR Part 4.
  2. If any conditions are paired (both arms, both legs, paired muscles), combine those first under 38 CFR 4.25, then add the 10% bilateral factor under 38 CFR 4.26.
  3. Combine all remaining ratings (and the bilateral-adjusted value, if any) using the 38 CFR 4.25 combined-ratings table, working from highest to lowest.
  4. Round the final combined value to the nearest 10 per 38 CFR 4.25(a).
  5. Apply the matching dollar figure from the published VA monthly compensation table, with the dependent add-on if combined rating is 30%+.
  6. Add SMC entitlements, apply TDIU if entitled, and apply any temporary 100% rating under 38 CFR 4.29 / 4.30.

If you understand step 3 — the combine-then-round — you understand 90% of the surprises that show up on VA decision letters.

Related guides

Sources cited in this guide

VetDisabilityCalc is an independent reference site operated by Zoom Lifestyle LLC. We are not VA-accredited and we do not prepare or present VA claims. The information in this guide is reference material based on the cited regulations and is not legal advice. For representation, use the official VA OGC accreditation directory. Helps us maintain this site: at the time of publication, no affiliate links appear on this article.