Ratings
How VA math works: why 50 + 30 = 70, not 80
The VA does not add your ratings together. It uses a system that quietly costs veterans the number they thought they earned. Here is exactly how it works, in plain English.
You get your decision letter. It lists a 50 percent rating for one condition and a 30 percent for another. In your head that is 80. Then you see the combined number: 70 percent. It feels like the VA shorted you.
It did not. It used a system called combined ratings, and once you see how it works, your number stops being a mystery. This is the same math that decides whether you cross an important line, like 90 to 100, so it is worth understanding before your next claim, not after.
The short version
The VA does not add your ratings. It treats you as 100 percent healthy to start, and each disability takes a percentage of whatever healthy part is left, not of the original whole. Then it rounds the final number to the nearest 10. That is why the combined number is always lower than simple addition.
Why the VA does not just add
Imagine you start at 100 percent of a whole, healthy person. Your first disability is rated 50 percent. That takes 50 percent of the whole, and leaves you 50 percent healthy.
Now the second disability, rated 30 percent, comes in. Here is the part everyone misses: it does not take 30 percent of the original 100. It takes 30 percent of the 50 percent that is left. Thirty percent of 50 is 15. So your combined disability is 50 plus 15, which is 65.
The logic is that you cannot lose more than 100 percent of yourself. Each condition can only affect the healthy part that remains, so every rating you add is worth a little less on paper than the one before it.
The worked example, step by step
Take a 50 percent and a 30 percent rating:
| Step | What happens | Running total |
|---|---|---|
| Start | You begin as 100 percent healthy. | 0% disabled |
| Apply 50% | Takes 50 of the 100. Leaves 50 healthy. | 50% disabled |
| Apply 30% | Takes 30% of the remaining 50 = 15. | 65% disabled |
| Round | 65 rounds to the nearest 10. | 70% |
So 50 and 30 combine to 65, which rounds to 70. Not 80.
The rounding rule that trips people up
After the VA combines everything, it rounds the final value to the nearest number divisible by 10. A value ending in 1 through 4 rounds down. A value ending in 5 through 9 rounds up. Sixty-five ends in 5, so it rounds up to 70.
This is also why two 30 percent ratings do not equal 60. Thirty of the whole leaves 70 healthy; 30 percent of that 70 is 21; 30 plus 21 is 51; and 51 rounds down to 50. Two 30s equal 50, not 60.
Do the biggest first
The VA combines your disabilities starting with the highest rating and working down. The order does not change the final answer, but starting from your largest rating is the fastest way to check the math yourself.
The bilateral factor: a small bonus most veterans miss
There is one wrinkle that works in your favor. If you have disabilities affecting both arms, both legs, or paired muscle groups, the VA first combines those bilateral ratings, then adds an extra 10 percent of that combined value before folding it in with everything else. It is a small boost, but on a claim sitting near a rounding line, that 10 percent can be the difference between one bracket and the next.
Why this matters for your strategy
Because each new rating is worth less than the last, climbing the ladder gets harder the higher you go. Getting from 0 to 50 is fast. Getting from 90 to 100 can take a surprisingly large new rating, because you are only ever chipping away at the sliver of healthy left. That is not a reason to stop filing. It is a reason to know your real combined number before you decide what to claim next, so you are chasing the conditions that actually move it.
Where to verify this yourself
The method is set in law, not left to a rater's judgment. You can read it in the Combined Ratings Table at 38 CFR §4.25, and VA publishes the same table on VA.gov. If a combined number on your letter does not match the table, that is worth raising with a free accredited representative, because rating math errors do happen.
Run your own numbers in seconds
The VA Claims Copilot has a built-in combined-ratings calculator that does this math for you, bilateral factor and all, and shows every step. Or upload your decision letter and it will explain your actual combined rating in plain English.
This is general education, not legal advice, and not from the VA. Your claim depends on your records, your evidence, and your exam. For advice on your specific situation, work with a free VA-accredited representative or a Veterans Service Organization. We are not the VA and are not affiliated with the VA.