I Built a VA Rating Calculator. It Was Wrong. Here's How I Found Out.

I'm a veteran. Air Force, 2003–2009. I've run my own claim — supplemental claims, denials, the whole thing. So when I built a VA rating calculator, I thought I understood the math.

I didn't.

I found out because I checked the calculator against my own VA award letter. The number was wrong. Not by a little.

Then I checked the rating math against the VA's own combined ratings table, and found something worse.

Here's all of it, because if you're a veteran using any free calculator online, you should know how to check whether it's telling you the truth.

The formula almost everyone uses

Ask how VA math works and you'll get some version of this:

Rank your ratings highest to lowest. For each one, compute combined = A + B × (100 − A) / 100. Round to the nearest 10% at the end.

That's the "whole person" method, and the idea is right: the VA doesn't add your ratings. A 50% and a 30% don't make 80% — they make 65%.

But there's a detail buried in that instruction, and it's the whole ballgame:

"Round to the nearest 10% at the end."

At the end. Meaning: run the multiplication straight through, carrying decimals, and only round once, at the finish.

That is not what the VA does.

What the VA actually does

38 CFR § 4.25 doesn't describe a formula. It describes a table — Table I, the Combined Ratings Table. You can download it from VA.gov right now.

Open it and look at the left column: 19, 20, 21, 22... all the way to 94.

Whole numbers. Every one of them.

That matters more than it looks. To combine three or more ratings, the table works by chaining: you look up your two highest, get a number, and then take that number back to the left column to combine with your third.

So ask yourself — what happens when the formula hands you 94.6?

You can't look it up. There is no row 94.6. The table has nowhere to put it.

The VA's table doesn't carry decimals between steps, because it can't. It rounds at every step, by construction. That isn't an interpretation of the regulation. It's the only way the table can be used at all.

And that changes the answer.

The 90 vs 100 problem

Take a veteran rated 90%, 40%, and 10%.

Using the VA's table:

Final combined value: 95. And § 4.25 says a combined value ending in 5 is adjusted upward.

95 → 100%.

Using the common formula, carrying decimals:

1 − (0.10 × 0.60 × 0.90) = 0.946  →  94.6  →  rounds to 90%

94.6 → 90%.

Same veteran. Same ratings. Two answers.

At 2026 rates, 90% pays $2,362.30 a month. 100% pays $3,938.58.

That's $1,576.28 a month. $18,915 a year.

How common is this?

I ran every combination of 2 to 6 ratings through both methods.

145 combinations disagree. In 116 of them, the decimal method reports 90% for a veteran the VA's table puts at 100%.

And here's the part that stopped me cold: every single disagreement runs in the same direction. The decimal method never once reported more than the VA's table. Not in a single case out of thousands.

If it's wrong, it's wrong against you.

Don't take my word for it. Check the table.

This is the part I want you to actually do.

1. Open the VA Combined Ratings Table.
2. Take your two highest ratings. Find your highest in the left column, your second in the top row. That cell is your running total.
3. Take that number back to the left column, and combine it with your next rating. Repeat.
4. When you're out of ratings, round to the nearest 10. A value ending in 5 rounds up.

If you're a veteran at 90% and this exercise lands you on 95 — go talk to your VSO.

I'm not telling you the VA made a mistake on your claim. The VA uses its own table; it usually gets this right. The calculators are what get it wrong, and if you've been using one to decide whether it's worth filing for an increase, you may have been told you're further from 100% than you actually are.

The bilateral factor, which almost nobody applies

There's a second one.

If you have compensable ratings on both arms or both legs — bilateral radiculopathy, both knees, both feet — § 4.26 gives you a bonus. You combine the paired ratings first, then add 10% of that value before combining with everything else.

30% and 20% on both legs:

• Not bilateral: they combine to 44 → 40%
• Bilateral: 44 + 4.4 = 48.4 → 50%

An entire rating band. Roughly $580 a month at that level.

Most free calculators don't even ask whether your conditions are paired. If yours doesn't have that checkbox, it can't be applying the factor.

What I did about it

I rewrote the math to use the table method — rounding at every step, exactly as § 4.25 requires.

Then I transcribed the VA's published Table I — all 684 cells — into an automated test.

Our implementation matches 684 out of 684. Every cell.

That test runs on every change, so the math can't quietly drift. If it ever disagrees with the VA's table, the build fails and nothing ships.

I also added the bilateral factor, and a reverse calculator that answers the question every veteran at 90% is actually asking: what gets me to 100? (The answer surprises people: you need a combined value of 95, not 100.)

And the bug my award letter caught

The rating math was one thing. The compensation math was another.

My calculator said I should be getting $2,849.30 a month. My award letter said $2,802.30.

$47 off. So I dug in.

The VA doesn't charge a flat rate per child. It publishes columns — "veteran with spouse and one child" — and then a separate, smaller "each additional child" rate for every kid after the first. My code was applying the first-child rate to all of them.

If you have more than one kid, that error was inflating your number.

I only caught it because I'm the customer. I checked the tool against my own life, and it failed.

Check your math

Every tool on Claims.vet is free. No account, no email required to use the calculator, no upsell, no "free claim review" funnel waiting at the bottom.

I'm not a VSO. I'm not accredited, and I can't help you file. Claims.vet does math. That's all it does. For help with an actual claim, go to an accredited representative — it's free, and it's what they're there for.

But the math should be right. And you should be able to check it yourself.

The table's right here. Go look.

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Claims.vet is a free set of tools built by a veteran. Estimates only — the VA's decision controls. Not legal or claims advice, and not affiliated with the Department of Veterans Affairs.