If you’ve ever looked at your VA ratings and thought, “There’s no way this adds up right,” you’re not crazy. The VA doesn’t add disability ratings the way normal people would. It uses its own formula, which is why a set of ratings that looks like it should equal 80% might only come out to 70%.
That’s what people mean when they talk about “VA math.” And yes, it’s weird.
The easiest way to understand it is this: the VA doesn’t treat each rating as coming off the full 100%. Instead, each new rating gets applied to whatever’s left after the earlier ratings are taken into account. So every new percentage is working with a smaller number. That sounds more complicated than it is, but it helps explain why Veterans are constantly staring at rating decisions like they were written by a committee of drunk accountants.
Let’s break it down.
The Basic Idea
The VA starts with the assumption that you’re 100% efficient. Once it assigns one disability rating, it subtracts that from the 100%. Then, if you have another service-connected condition, the VA applies that second rating only to the part of you it says is still “efficient.” So if you’re rated 50% for one condition, the VA says you still have 50% remaining efficiency. If you then get another 30% rating, it doesn’t just add 30 to the original 50. It applies that 30% to the 50% that’s left.
That’s why the numbers don’t work the way you’d expect.
A Simple Example
Let’s say you have:
- 50% for migraines
- 30% for a mental health condition
Most people would think that equals 80%. Under VA math, it doesn’t. Here’s how the VA does it:
- Start with 100%.
- Take away 50%. That leaves 50%.
- Now apply the 30% rating to the remaining 50%.
- Thirty percent of 50 is 15.
- So now you’ve got 50 + 15 = 65%.
Then the VA rounds to the nearest 10. So 65% becomes 70%. That means:
- 50% + 30% = 65% combined = 70% overall
Not intuitive. Not especially intelligent. But that’s the system.
Another Example
Now let’s say your ratings are:
Here’s what that looks like:
- Start with 100%.
- A 70% rating leaves 30% remaining.
- Then take 20% of that 30. That gives you 6.
- Now you’re at 76% combined.
- That leaves 24% remaining.
- Then take 10% of 24. That gives you 2.4.
- Now you’re at 78.4%.
- The VA rounds that to 80%.
So even though 70 + 20 + 10 looks like 100% if you add it normally, the VA comes out with 80% combined. That’s why so many Veterans think the VA made a mistake when they first see the number. Sometimes the VA did make a mistake. But a lot of the time, it’s just this bizarre formula doing what it does.
Why the Order Matters
The VA generally starts with the highest rating and works down from there. That matters because each percentage is applied to what’s left, not to the original 100%. So the big ratings hit first, and the smaller ones nibble away at the remainder.
That also explains why adding another 10% rating doesn’t always increase your overall combined rating. Sometimes it moves the number a little, but not enough to get you into the next rounded bracket. For example, if your current combined value is 84%, and a new rating pushes you to 85%, that rounds to 90%. But if you’re sitting at 81% and the new rating only gets you to 83%, you’re still at 80% for payment purposes.
So yes, you can win another issue and still see no change in your monthly compensation. You just got VA'd.
Rounding Is a Big Deal
Once the VA finishes the calculation, it rounds to the nearest 10%. If the number ends in 5 or higher, it rounds up. If it ends in 4 or lower, it rounds down. So:
- 64% rounds to 60%
- 65% rounds to 70%
- 74% rounds to 70%
- 75% rounds to 80%
That rounding rule matters a lot more than people realize. In many cases, the real fight isn’t just about getting service connection. It’s about getting the right percentage so the combined rating crosses into the next bracket. A small increase can make a real difference.
The Bilateral Factor
Then there’s the bilateral factor, because the VA system wasn’t quite confusing enough yet. If you have disabilities affecting both sides of the body, like both knees, both shoulders, both ankles, or both arms, the VA may apply an extra bump called the bilateral factor. In plain English, the VA recognizes that having problems on both sides of the body can create more overall impairment than just looking at each side separately. So it combines those ratings first, adds an extra 10% of that combined value, and then folds that result into the rest of the calculation.
You don’t need to memorize the formula. What matters is knowing that it exists, because it can change the final number. And if the VA misses it, that mistake can cost you money.
Why Your Combined Rating Can Feel Lower Than It Should
This is where a lot of frustration comes from. Let’s say you have ratings of:
A normal person looks at that and thinks, “That’s 110%. How am I not basically at 100?” Under VA math, here’s what happens:
- Start with 100.
- Take away 50, leaving 50.
- Apply 30% to the remaining 50, which gives you 15. Now you’re at 65.
- Apply 20% to the remaining 35, which gives you 7. Now you’re at 72.
- Apply 10% to the remaining 28, which gives you 2.8. Now you’re at 74.8.
- That rounds to 70%.
So four ratings that would add up to 110% normally can still leave you at a 70% combined rating under the VA system. We know. Once again...you got VA'd.
Why This Matters
Understanding how combined ratings work affects claim strategy. Sometimes a condition that looks minor on paper is exactly what gets you into the next bracket. Sometimes the real issue isn’t whether the VA granted service connection, but whether it assigned too low a rating. And sometimes the VA gets the individual ratings right but screws up the combined calculation, misses the bilateral factor, or uses the wrong effective date.
Those are all separate issues, and all of them matter. When you review a rating decision, you should be looking at at least three things:
- Did the VA assign the right rating for each condition?
- Did it combine those ratings correctly?
- Did it make the overall evaluation effective on the right date?
If any of those are wrong, the decision may be costing you benefits.
The Bottom Line
VA math feels wrong because it's not designed to work in your favor, it's designed to offer diminishing returns. The VA doesn’t just add your ratings together. It applies each new percentage to what remains after the earlier ratings are accounted for, then rounds the final number to the nearest 10%. Once you understand that, the decisions start making a little more sense, even if the system itself still deserves to be trashed.
And if your overall rating seems off, don’t assume the VA got it right just because the letter looks official. The individual ratings might be wrong. The combined math might be wrong. The bilateral factor might’ve been missed. The effective date might be wrong.
Any one of those can affect how much you’re paid.
So if the numbers look strange, it’s worth checking them carefully. With the VA, confusion is common. Accuracy is a separate question.
