VA Math, Why 50 Plus 30 Is Not 80
VA math is the way VA combines several disability ratings into one combined rating. It is not simple addition. VA uses the whole person method in 38 CFR 4.25, so two ratings of 50 and 30 give a combined rating of 70, not 80. This guide walks through the method, the rounding rule and the bilateral factor with tables you can check yourself.
Why 50 plus 30 is not 80
VA starts from the idea that you are 100 percent efficient. A 50 percent rating means VA sees you as 50 percent efficient. The next rating of 30 percent applies only to the 50 percent that is left, not to the whole 100. Thirty percent of 50 is 15, so the combined value is 65. VA then rounds 65 to the nearest 10, which gives 70.
The whole person method step by step
- 1Sort your ratings from highest to lowest.
- 2Start with the highest rating. Subtract it from 100 to get your remaining efficiency.
- 3Take the next rating as a percent of the remaining efficiency and add it to the combined value.
- 4Subtract again to get the new remaining efficiency and repeat for each rating.
- 5Round the final combined value to the nearest 10. Values ending in 5 round up.
The VA table in 38 CFR 4.25 rounds each step to a whole number. The final rating is still rounded only once, to the nearest 10. Our va combined rating table page shows how to read those whole numbers.
Worked example with 50 and 30
| Step | Rating | Remaining efficiency | Combined value |
|---|---|---|---|
| 1 | 50 | 50 | 50 |
| 2 | 30 | 35 | 65 |
| Final | rounded | 70 |
Thirty percent of the remaining 50 is 15. The combined value is 65, and 65 rounds up to 70.
Worked example with 70, 40 and 10
| Step | Rating | Remaining efficiency | Combined value |
|---|---|---|---|
| 1 | 70 | 30 | 70 |
| 2 | 40 | 18 | 82 |
| 3 | 10 | 16.2 | 83.8 |
| Final | rounded | 80 |
After 70, the remaining efficiency is 30. Forty percent of 30 is 12, so the combined value is 82 and 18 is left. Ten percent of 18 is 1.8, so the combined value is 83.8. The table shows this as 84, and 84 rounds to a final rating of 80.
The rounding rule
VA rounds only the final combined value to the nearest 10. A value of 84 becomes 80. A value of 85 becomes 90, because values ending in 5 round up. A value of 94 becomes 90, and a combined rating can reach 100 only when the combined value is 95 or higher.
The bilateral factor with both knees
When a condition affects paired limbs, such as both arms or both legs, 38 CFR 4.26 adds a small extra amount. Here is an example with a 10 percent rating for each knee and a 30 percent rating for another condition.
| Step | Rating | Remaining efficiency | Combined value |
|---|---|---|---|
| 1 | Left knee 10 | 90 | 10 |
| 2 | Right knee 10 | 81 | 19 |
| 3 | Bilateral factor, 10 percent of 19 | 20.9 | |
| 4 | Bilateral value used | 21 |
The two knees combine to 19. Ten percent of 19 is 1.9, so the bilateral value is 20.9, which is used as 21. VA then combines 21 with your other ratings in order of severity.
| Step | Rating | Remaining efficiency | Combined value |
|---|---|---|---|
| 1 | 30 | 70 | 30 |
| 2 | Bilateral 21 | 55.3 | 44.7 |
| Final | rounded | 50 |
Twenty one percent of 70 is 14.7, so the combined value is 44.7. The table shows 45, and 45 rounds up to a final rating of 50.
Common VA math mistakes
- Adding ratings together instead of combining them.
- Rounding after every step instead of only at the end.
- Starting with the lowest rating instead of the highest.
- Forgetting the bilateral factor when both arms or both legs are rated.
- Counting a 0 percent rating as if it changes the combined value. It does not, but it still matters for the record.
Check your own numbers
Enter each condition and its rating in the va combined rating calculator. It sorts your ratings, applies the bilateral factor and shows every step of the VA math in a table.
What is VA math
VA math is the whole person method VA uses in 38 CFR 4.25 to combine several disability ratings. Each rating applies only to the efficiency left after the ratings before it.
Why does VA not add my ratings
VA treats you as one whole person. A second rating can only reduce the efficiency that is still left, so adding ratings would count the same part of you twice.
How do I reach a 100 percent combined rating
The combined value must reach 95 or higher before rounding. Many veterans with several high ratings still land at 90, because each new rating applies to a smaller remaining efficiency.
When does the bilateral factor apply
It applies when a condition affects paired limbs, such as both arms or both legs, under 38 CFR 4.26. You combine those ratings first, add 10 percent of that value and then combine the result with your other ratings.
Is the calculator result my official rating
No. The result follows the published method, but only VA decides your rating. MilitaryMedicine is an independent service and not part of the VA.