Veteran Help

The VA doesn’t add your disability ratings together, it multiplies what’s left. That’s why a veteran rated 50%, 30%, and 20% ends up at 70% and not 100%. The system uses what the regs call “remaining efficiency”: each new disability is applied to whatever percentage of you the VA still considers healthy, not to the original 100%.

If you want to verify your VA rating yourself—and you should, because miscalculations happen—you need three things: the order of your individual ratings, the Combined Ratings Table from 38 CFR § 4.25, and the rounding rule. We’ll walk through all three with worked examples.

What Is VA Math?

VA math is the formula in 38 CFR § 4.25 the VA uses to combine multiple service-connected disability ratings into a single overall rating. A 60% disability is treated as 40% efficient; a further 30% disability leaves only 70% of that 40%, which works out to 28% efficient overall. The combined rating is what’s left after all those reductions, subtracted from 100, and then rounded to the nearest 10%.

The whole system is built on one idea: a healthy person starts at 100% efficient. Each service-connected condition reduces that efficiency by a percentage of whatever’s left, not a percentage of the full 100. That’s why stacking VA ratings produces diminishing returns, and why it gets brutal once you’re already past 50%.

How the Math Works

Here’s the procedure exactly as the VA runs it. You can do it by hand with a calculator, or use the Combined Ratings Table to skip the arithmetic. Both produce the same answer.

Step 1: Order ratings from highest to lowest. Always start with the largest. For a veteran with disabilities at 50% and 30%, the order is 50%, then 30%.

Step 2: Calculate remaining efficiency after the first rating. Subtract the first rating from 100. A 50% disability leaves 50% efficiency.

Step 3: Apply the next rating to what’s left. Multiply the remaining efficiency by the next rating. 50% × 30% = 15%. That 15% is the additional disability the second condition contributes.

Step 4: Add it to the running total. 50% + 15% = 65% combined disability. Remaining efficiency is now 35%.

Step 5: Repeat for each additional rating. If the veteran also had a 20% rating, you’d take 35% × 20% = 7% additional disability, bringing the combined value to 72%.

Step 6: Round to the nearest 10%. The combined value is converted to the nearest number divisible by 10, and any value ending in 5 rounds up. 72% rounds down to 70%. A combined value of 75% would round up to 80%.

The Combined Ratings Table in 38 CFR § 4.25 is just a lookup version of this same calculation: find your highest disability rating in the left column, your next-highest in the top row, and the cell where they meet is the combined value before rounding. Then you take that combined value back into the table against your next rating, and so on.

Quick Example: 50%, 30%, and 20%

Let’s run this for a real combination. Say a veteran has PTSD at 50%, a back condition at 30%, and tinnitus at 20%.

Step	Calculation	Combined value	Remaining efficiency
Start	—	0%	100%
Apply 50%	100% × 50% = 50%	50%	50%
Apply 30%	50% × 30% = 15%	65%	35%
Apply 20%	35% × 20% = 7%	72%	28%
Round	72% → nearest 10%	70%	—

The veteran’s combined rating is 70%.

If you used the lookup table instead: For 50% and 30%, find 50 in the left column and 30 in the top row — the combined value where they meet is 65. Then take that 65 back into the table against the 20% rating to get 72. Round to 70. Same answer.

Why 10 + 10 is Not 20

This catches a lot of veterans off guard, so it’s worth walking through. Start at 100% efficiency. Apply the first 10% rating: 100 × 10% = 10% disability, leaving 90% efficiency. Apply the second 10%: 90% × 10% = 9% additional disability. Total combined value: 19%. Two 10% ratings combine to 19%, which will then round to 20%.

But the VA reports the unrounded 19% combined value when it shows up alone. The VA’s own guidance specifically notes that two disabilities each rated at 10% combine to 19% — that’s the value carried forward if a third disability rating gets added later, before the last round to 10% for the final combined disability rating.

The Bilateral Factor

This is the most-missed rule in VA math. If you have service-connected disabilities affecting both arms, both legs, or paired skeletal muscles, even if the conditions on each side are different, you get an extra 10% bonus before the rest of the math runs.

Here’s how it works under 38 CFR § 4.26. Combine the bilateral disability ratings as usual, then add (not combine) 10% of that combined value before any further calculations or rounding. The bilateral disabilities, including the 10% factor, are then treated as a single disability for the rest of the calculation.

Run the regulation’s own example. The veteran has 60%, 20%, 10%, and 10%, with the two 10% ratings being bilateral knee conditions.

Combine the bilateral pair first. 10% combined with 10% = 19% combined value.
Add the 10% bilateral factor. 19% × 10% = 1.9%, which is added (not combined). 19 + 1.9 = 20.9%, rounded to 21%.
Reorder the disabilities by severity. The order is now 60, 21, and 20.
Combine the rest with VA math. 60% + (40% × 21%) = 68.4. Then 68.4% combined with 20% (using remaining efficiency 31.6 × 20% = 6.32) = 74.72%. Rounded to 70%.

Without the bilateral factor, the combined value (and subsequent VA disability benefits) would have come out lower. The 10% bonus before the main combination is what nudges the math up. The bilateral factor only applies when there’s at least a compensable rating in each of two paired extremities or paired skeletal muscles.

A few rules that trip people up:

The conditions on each side don’t have to match. A right knee meniscus tear and left knee arthritis both count as bilateral lower extremity. The factor still applies.
0% ratings can still trigger it for some pairings, as long as the other side is compensable.
Mental health conditions never qualify. PTSD, anxiety, and depression aren’t paired extremities, so the bilateral factor doesn’t touch them.
The VA’s automated systems sometimes miss it. Check your rating decision letter. If you have ratings on both arms or both legs and you don’t see the bilateral factor referenced in the math, that’s a likely error.

There’s also an exception added to the rule in 2023 worth knowing about. If applying the bilateral factor would actually produce a lower combined rating than excluding the bilateral disabilities and combining them separately, the VA is now required to use whichever method gives the veteran the higher rating. This was a small but real liberalizing change. It mostly matters at the high end where rounding can flip a 95% combined value to a 100%- full disability compensation.

How the Rounding Works

Two rules to keep straight.

Rule 1: Round only at the end. Don’t round intermediate combined values. Carry the unrounded number forward until you’ve combined every rating.

Rule 2: 5 rounds up, anything below 5 rounds down. A combined value of 74% rounds down to 70%. A combined value of 78% rounds up to 80%. 75% rounds up. Per the federal regulation, when the combination produces a decimal, the decimal is converted to a whole number first (with .5 or higher adjusted upward), and then that whole number is converted to the nearest degree divisible by 10.

The rounding rule is also why each percentage point inside a 10% bracket doesn’t help you. A 73% combined value pays the same as 70%. A 74% combined value still pays at 70%. You only see a payment increase when you cross into the next bracket.

When It Really Matters: The 90% → 100% Jump

The combined ratings system gets harder to climb the closer you get to 100%, which makes the highest brackets the most expensive ones to miss. A veteran rated at 100% disability (with no dependents) receives $3,938.58 monthly under the 2026 rates. The 90% rate for the same veteran is roughly $1,580 lower per month, or about $19,000 a year.

That’s why bilateral factor errors and rounding mistakes near the top of the schedule are the ones to watch. A veteran with a combined value of 94.5% can be the difference between $2,360 and $3,938 per month depending on whether the math was run correctly.

There’s a separate path called Total Disability Based on Individual Unemployability (TDIU) for veterans who can’t work because of service-connected conditions but whose math doesn’t get them to 100%.

TDIU pays at the 100% rate when a veteran has one service-connected disability rated at 60% or more, or two or more disabilities with at least one at 40% or more and a combined rating of 70% or higher, and can’t maintain substantially gainful employment.

How to Check Your Own Combined Rating

Three quick checks before you assume the VA got it right.

List your ratings highest to lowest from your decision letter. Make sure each one is service-connected and currently active. Non-service-connected conditions don’t enter the math.
Run the calculation by hand or use a calculator. The VA’s own combined ratings table is in 38 CFR § 4.25 and on VA.gov. Compare the result to what’s on your decision letter.
Check for the bilateral factor. If you have ratings on both arms, both legs, or paired skeletal muscles, look for “bilateral factor” language in your decision letter or codesheet. If it’s missing and you qualify, that’s an appealable error.

If the math doesn’t match what’s on your decision letter, you have options.

A clear arithmetic error can be addressed with a request for correction as Clear and Unmistakable Error under 38 CFR § 3.105(a) but if your claim is still within the appeal window, a higher level review is a simpler and quicker process.

A disagreement about whether the bilateral factor should apply, or whether a condition should be combined separately, is usually better handled with a Higher-Level Review or a Supplemental Claim.

Frequently Asked Questions

Why is my VA combined rating lower than the sum of my individual ratings?

Because the VA uses “whole person” math, not addition. Each rating reduces the percentage of you still considered healthy, then the next rating only applies to what’s left. It becomes harder to reach 100% without one extremely high rating or several very high ones.

How does the VA round combined ratings?

The VA rounds the final combined value to the nearest multiple of 10. Values ending in 5 round up. So 75% becomes 80%, but 74% becomes 70%. Don’t round any intermediate values — only the final number.

What is the bilateral factor and how do I know if it applies to me?

The bilateral factor is a 10% bonus added to the combined value of service-connected disabilities affecting paired extremities (both arms, both legs, or paired skeletal muscles) before the rest of the math runs. Different conditions on each side still qualify—they don’t have to be the same diagnosis.

Can I get to 100% if my VA math doesn’t add up to 100%?

Yes, through TDIU (Total Disability Based on Individual Unemployability). If you have one disability rated 60% or more, or two or more disabilities with at least one at 40% and a combined rating of 70% or higher, and you can’t keep substantially gainful employment because of those conditions, you can be paid at the 100% rate even if your combined math stops at 70%.

Where can I find the official combined ratings table?

The official table is published in 38 CFR § 4.25 and posted on VA.gov. The bilateral factor rule is in 38 CFR § 4.26. These are the only authoritative sources—every calculator and explainer is just a lookup wrapper around those two regulations.

How VA Math Works: Combined VA Disability Ratings