How VA combined disability ratings are calculated

More people misunderstand this calculation than any other in the field, and the misunderstanding is entirely reasonable: every instinct says percentages add. A veteran with a 50%, a 30% and a 20% rating naturally expects 100%. The actual combined rating is 70%, and the difference is not a rounding error — at current rates it is a substantial sum every month, for life.

The method is not arbitrary. Once you see what it is modelling, it becomes obvious why it cannot be addition.

The whole-person model

The regulation treats a veteran as starting at 100% efficiency. Each disability removes a percentage of what remains, not a percentage of the original whole.

The reasoning is that a person cannot be more than entirely disabled. If ratings added, four 30% conditions would produce 120%, which is meaningless. So each successive condition is applied to the efficiency still left after the previous ones.

Three rules govern the procedure and each of them changes answers:

Sort descending. Ratings are combined starting with the largest. The regulation’s table is built this way, and while the mathematics of combining two numbers is commutative, the intermediate values — and therefore the effect of rounding — are not handled identically if you work up from the smallest.

Use the whole-number table at every step. Each Table I lookup produces a whole number, and that whole number is the input to the next lookup. Carrying an unrounded decimal forward is not the §4.25 procedure.

Round to the nearest 10 only after the last lookup. A final table value of 74 becomes 70; a value of 75 becomes 80.

The diminishing return, and what it means for a claim

Notice what happened across those three steps. The 50% rating was worth 50 points, the 30% was worth 15, and the 20% was worth 7. The same rating is worth progressively less the more you already have.

This has a practical consequence that changes how a claim is approached.

The corollary matters more, and points the other way: the ratings you claim first are worth the most. A veteran with several conditions should understand that the order in which they are eventually granted does not matter to the final combination — but the completeness of the claim does. A condition never claimed contributes nothing, and the smaller conditions are worth the most while the combined total is still low.

The bilateral factor

Where compensable disabilities affect both arms, both legs, or paired skeletal muscles, an additional allowance applies. The reasoning is that losing function in both of a pair is more disabling than the sum of losing it in each separately: a person with one bad knee compensates with the other, and a person with two cannot.

Calculator scope: the profile calculator represents paired upper and lower extremities only. It does not classify paired skeletal-muscle disabilities. Have VA or a VA-accredited representative review those cases; do not approximate them by selecting an upper or lower extremity.

“Both” is literal. Two right-leg conditions do not qualify by themselves; the record must include a compensable condition on the left and one on the right of the paired region. If both upper and both lower extremities qualify, §4.26(b) combines all of those qualifying ratings together and adds one factor. It does not create separate upper- and lower-extremity factors.

The procedure has a specific order, and this is where careful people go wrong.

1. Combine the bilateral ratings with each other first, under the ordinary method.
2. Add 10% of that combined value to it. This is the bilateral factor.
3. Convert that subtotal plus factor to the nearest whole number.
4. Only then combine that one whole-number result with the non-bilateral ratings.

The veteran-favorable exception effective April 16, 2023

The factor usually raises or preserves the result. In rare high-rating combinations it can lower the final evaluation because of whole-number and final rounding. Section 4.26(d), effective April 16, 2023, requires VA to remove one or more otherwise bilateral ratings from the factor calculation and combine them separately when that produces the higher evaluation.

The Federal Register gives the decisive example. Other disabilities combine to 93%, and there are left/right 10% ratings. With the factor, 10 and 10 become 19; adding 1.9 gives 20.9, which becomes 21. Combining 93 and 21 produces 94 and a final 90%. Combining the 10s separately instead produces 94 and then 95, which rounds to 100%. The current calculator compares the permitted paths and reports the veteran-favorable one, with the table lookups shown in its trace.

Why the combined figure is not the whole answer

A combined rating is an input to compensation, not the compensation itself, and three things sit between them.

Dependents. Compensation at 30% and above is adjusted for a spouse, children and dependent parents. Two veterans at the same rating receive different amounts, and a change in family status requires notifying the department to be reflected.

Special monthly compensation. Certain losses and combinations are compensated above the ordinary schedule, on a separate structure that does not follow the combining rules at all.

Total disability based on individual unemployability. A veteran unable to maintain substantially gainful employment because of service-connected conditions may be paid at the 100% rate while holding a lower combined rating. This is the route that matters most for the veteran stuck at 90%, and it turns on employability evidence rather than on finding more percentage points.

For military retirees there is a further interaction covered elsewhere on this site: VA compensation requires waiving an equal amount of retired pay, which is generally advantageous because compensation is not taxable — and Concurrent Retirement and Disability Pay and Combat-Related Special Compensation restore part or all of the waived amount for those who qualify. A rating decision therefore changes two income streams at once, and modelling only one of them produces an answer that is wrong in a direction that feels right.