Why 50% + 30% VA disability is NOT 80%

Why 50% + 30% VA disability is NOT 80%

The first time a veteran sees their VA rating decision, the math looks broken. You've got a 50% rating for one condition and a 30% for another, and you're sitting there doing fourth-grade addition: 50 plus 30 is 80, right?

Wrong. The VA says 65. And after a step you didn't know about, it becomes 70.

This trips up almost everyone, so let me walk through what's actually happening. I'm a developer who got tired of explaining this by hand, so I ended up building a free calculator for it. More on that at the end. First the logic, because once you see it you'll never be confused again.

The "whole person" idea

The VA doesn't treat you as a stack of percentages it can just add up. It treats you as a whole person who starts at 100% healthy, and each disability chips away at what's left, not at the original 100.

Think of it like a discount that compounds. A 50% off coupon followed by a 30% off coupon does not give you 80% off. The second coupon only applies to the price that survived the first one. Same deal here.

This is laid out in the federal regs, 38 CFR § 4.25, the "Combined Ratings Table." That's the official source if you want to read the dry version.

The actual formula

Order your disabilities from highest to lowest. Then peel them off one at a time against your remaining healthy percentage.

Start: 100% healthy.

Apply the 50% disability first:

remaining = 100 - 50 = 50% healthy

Now apply the 30% to what's left, the 50, not the original 100:

30% of 50 = 15
remaining = 50 - 15 = 35% healthy

So you're 35% healthy, which means 65% disabled. That's where the 65 comes from.

If you want it as one line:

combined_disability = 100 - (100 * (1 - 0.50) * (1 - 0.30))
                    = 100 - (100 * 0.50 * 0.70)
                    = 100 - 35
                    = 65

Every extra condition just adds another (1 - rating) factor to that product. Three disabilities at 50, 30, 20:

100 - (100 * 0.50 * 0.70 * 0.80) = 100 - 28 = 72

Then it rounds

Here's the part people miss. The VA takes that combined number and rounds to the nearest 10.

65 rounds up to 70. So our 50-and-30 veteran walks away at 70%, not 65, and definitely not 80.

72 from the three-disability example rounds down to 70.

The rule is plain rounding: 5 and up goes up, 4 and down goes down. A combined 64 becomes 60. A 65 becomes 70. This single step can mean a real jump in monthly compensation, which is why the order and the exact numbers matter so much.

Where the spouse and kids come in

Notice the dependents have not touched the math yet, and that's on purpose. Dependents do not change your rating. Your rating is your rating. What they change is the dollar amount attached to it, and only once you hit 30% or higher.

So the flow is two separate stages:

1. Combine all your disability percentages with the formula above. Round to the nearest 10. That gives you your rating, say 70%.
2. Look up the dollar figure for a 70% veteran, then add the dependent allowances on top: a spouse bumps it, each child under 18 bumps it, a child in school past 18 bumps it more, and dependent parents add too.

A single veteran at 70% and a married veteran at 70% with two kids get the same rating but different checks. The VA publishes these dollar amounts in its compensation rate tables, and they get adjusted every December for cost of living. I'm not going to print a specific 2026 dollar figure here, because these change yearly and the last thing you want is to plan around a stale number. Pull the current rate from the official VA tables, or run your own.

Run your own numbers

The honest takeaway: addition is the wrong tool, the formula is multiplicative against your remaining health, and rounding to the nearest 10 happens before any dependent money gets added.

If you'd rather not do the (1 - rating) multiplication by hand, that's the free tool I built. Punch in each disability percentage and your dependents and it does the combine, the round, and the dependent add-on for you: https://militarycalc.com/disability/combined-rating-calculator

Plug in your real ratings and check it against your decision letter. If your letter and the calculator disagree, that's worth a second look at how the VA combined them.