How VA Combined Disability Ratings Are Calculated (With Examples)

Few things confuse veterans more than VA math. You have a 50 percent rating and a 30 percent rating, you add them up, and you expect 80 percent — but your award letter says 70. This is not a mistake. The VA does not add your ratings together. It combines them using a specific method that almost always produces a lower number than simple addition, and once you understand the logic, the “missing” points make sense.

Why the VA does not just add ratings

The VA rates disability as a measure of how much of the “whole person” remains able to function. You start at 100 percent efficient — fully healthy. Each disability reduces your remaining ability, but each new rating is applied only to what is left, not to the original 100. So a second disability is measured against an already-reduced person, which is why the points add up to less than a straight total. You can never exceed 100 percent, because you cannot be more than fully disabled.

The step-by-step method

The VA uses a Combined Ratings Table (found in 38 CFR 4.25), but you can follow the same logic by hand:

• Order your ratings from highest to lowest.
• Start with the highest rating and subtract it from 100 to find your remaining efficiency.
• Apply the next rating to that remaining efficiency, and subtract the result.
• Repeat for each rating.
• At the very end, round to the nearest 10 percent.

A worked example

Say you have three ratings: 50 percent, 30 percent, and 20 percent.

• Start at 100 percent efficiency. Apply the 50 percent rating: 50 percent of 100 is 50, so you are 50 percent disabled with 50 percent efficiency remaining.
• Apply the 30 percent rating to the remaining 50: 30 percent of 50 is 15. Add that to your 50, and you are now 65 percent disabled, with 35 percent efficiency left.
• Apply the 20 percent rating to the remaining 35: 20 percent of 35 is 7. Add it, and you reach 72 percent disabled.
• Round 72 to the nearest 10: your combined rating is 70 percent.

Simple addition would have given you 100 percent. VA math gives you 70. That gap is the whole-person principle at work.

Why two 50s do not equal 100

Here is the example that frustrates veterans most. Two 50 percent ratings: start at 100, apply the first 50 to reach 50 percent disabled and 50 percent remaining. Apply the second 50 to that remaining 50 — which is 25 — and you reach 75 percent. Rounded, that is 80 percent, not 100. To hit a combined 100 percent schedular rating, you generally need one very high rating or a stack of several substantial ones, which is exactly why so many veterans pursue a 100 percent rating through Individual Unemployability instead.

The bilateral factor

One wrinkle can work in your favor. When you have disabilities affecting both arms, both legs, or paired skeletal muscles, the VA adds a “bilateral factor” — an extra 10 percent of the combined value of those paired ratings — before combining them with the rest. It is a small boost, but for veterans with matching left-and-right conditions it can nudge a rating over a threshold. The VA applies it automatically, but it helps to know it exists when you check the math.

Checking your own rating

You do not need to trust the award letter blindly. Order your ratings high to low, combine them one at a time against your remaining efficiency, apply the bilateral factor if it applies, and round at the end. Free combined-ratings calculators can do this instantly, but doing it once by hand is the best way to finally understand why VA math works the way it does — and to spot the occasional error in your favor. If your own calculation differs from the VA’s by a meaningful margin, it is worth asking for a review.

The rating thresholds that matter

Understanding the math is not just academic, because certain combined percentages unlock real benefits. At 30 percent, you can add dependents to your award for additional monthly pay. At higher levels the monthly amounts climb sharply, and a 100 percent rating opens the widest door — including benefits for your family, property tax relief in many states, and more. Because each step is worth real money, veterans often work to document a condition fully or pursue secondary conditions to reach the next threshold. Knowing how the combination works tells you how close you actually are.

Combined rating vs. Individual Unemployability

What if the VA math stalls you at 70 or 80 percent, but your service-connected conditions genuinely keep you from holding a steady job? That is exactly what Total Disability based on Individual Unemployability (TDIU) is for. TDIU pays at the 100 percent rate even when your combined schedular rating is lower, as long as you meet the criteria and cannot maintain substantially gainful employment. For many veterans whose combined rating plateaus below 100, TDIU — not more rating points — is the realistic path to the maximum benefit.

How a new condition changes your combined rating

Your rating is not frozen. Every time the VA adds a newly service-connected condition, it does not simply tack the new percentage onto your old total — it recombines everything from scratch using the same whole-person method. That is why adding a 20 percent condition to an existing 70 might move you only to 80, or sometimes not change the rounded total at all. It also means a relatively small new rating can occasionally push you over a rounding threshold and bump your overall percentage up a step. When you receive a new decision, re-run the combination yourself so you understand how the latest condition affected the whole, rather than expecting straight addition.

Where the official numbers come from

The combination method is not guesswork — it is codified in the Combined Ratings Table in 38 CFR 4.25, the same table the VA uses internally. Free online combined-ratings calculators simply automate that table, including the bilateral factor and the final rounding, so they are a quick way to check your award. If you want to verify a result with confidence, run it through one of those calculators and compare it against the steps above; if the numbers disagree with your decision letter by a full rating step, that is a flag worth raising with the VA or a representative.