Why 50% + 30% is not 80%
The VA does not add disability percentages with ordinary arithmetic. It uses the “whole person” approach in 38 CFR §4.25: each new rating applies only to the efficiency you have left after earlier ratings.
A veteran rated 50% is considered 50% efficient. A further 30% disability applies to that remaining 50%, which contributes 15 points — so 50 + 15 = 65 before rounding, not 80.
How the Combined Ratings Table works
In practice, the VA uses the Combined Ratings Table. Disabilities are sorted from highest to lowest. Each pair is looked up (or computed) as a whole-number combined value. That intermediate value is then combined with the next disability, and so on.
Only at the end does the VA convert the combined value to the nearest number divisible by 10. Values ending in 5 round up (65 → 70, 95 → 100).
- Sort ratings highest to lowest
- Combine one step at a time (whole-number table values)
- Do not round to the nearest 10% until the final step
- 5s round up when converting to compensation rating
Worked example
Ratings 60%, 40%, and 20%. Combine 60 with 40 → 76. Combine 76 with 20 → 81. Round 81 to the nearest 10% → 80% combined rating for pay.
Exact combined vs pay rating
The table value before final rounding (for example, 65 or 81) is not always what appears as your “pay rating.” Compensation uses the rounded figure (70 or 80). When people say a calculator is “wrong,” they are sometimes comparing an unrounded table value to a rounded award letter — or using float math that drifts from the official table.
What combined rating does not include by itself
- Dependent add-ons (spouse, children, parents) at 30%+
- TDIU (can pay at the 100% rate with a lower schedular rating)
- SMC-K add-ons or higher SMC levels that replace schedular pay
- Permanent and Total (P&T) status — a separate finding
Check your numbers
Enter each disability percentage in the free combined rating calculator. Review the step-by-step table math, then compare the rounded result to your decision letter. If you have paired extremity ratings, read the bilateral factor guide before turning bilateral mode on.