VA Math: Why 50% + 50% Equals 80% (Not 100%)

Every veteran eventually runs into the VA's strangest arithmetic: you have a 50% rating, you win another 50% rating… and your combined rating comes back 80%.

Not a typo. Not a mistake in your decision letter. It's called combined ratings, it's in 38 CFR § 4.25, and understanding it changes how you build your whole claim.

The whole-person concept

The VA starts from a simple premise: you can't be more than 100% disabled. So instead of adding ratings, it treats each new rating as taking a bite out of what's left of the "whole person."

The example that explains everything:

• Your first 50% rating takes 50% of the whole person. Remaining: 50%.
• Your second 50% rating doesn't take another 50 points — it takes 50% of the remaining 50%, which is 25 points.
• 50 + 25 = 75%, which the VA rounds to the nearest 10: 80%.

Every additional rating works the same way, always biting the remainder. That's why ratings pile up fast at first and crawl near the top — a veteran at 90% may need several new ratings to reach 100%, because each one only takes a fraction of the sliver that's left.

Why the order doesn't matter (but the count does)

The math produces the same combined number regardless of the order you combine them. What matters is how many compensable ratings you have and how big they are. Two practical consequences:

Small ratings matter more than they look. A "mere" 10% for tinnitus takes 10% of whatever remains — and at the margin between 89.9% and 90%, or 94.9% and 95% (which rounds to 100 territory when combined with others), small ratings decide big rounding outcomes.

Secondary conditions are the realistic path upward. A veteran stuck at 70% usually can't reach 100% by pushing one condition higher. But secondary conditions — the ones caused by conditions you're already rated for — add new bites of the remainder. That's why they're often the difference-maker.

The bilateral factor: the 10% bonus most veterans miss

When you have rated conditions affecting both arms or both legs (in any combination — left knee + right ankle counts), the VA combines those first and adds 10% of their combined value before folding in everything else.

It exists because losing function on both sides is more disabling than the raw math suggests. It's also one of the most commonly missed additions — if you have bilateral ratings and your decision letter never mentions the bilateral factor, that's worth a hard look.

What this means for your claim strategy

1. Never eyeball your combined rating — the math is unintuitive by design. Compute it properly.
2. Count your conditions before chasing increases. Adding a valid new claim (especially a secondary) often moves the combined number more than fighting one rating up a tier.
3. Check the rounding line. A combined 75% rounds to 80; a 74 rounds to 70. Sometimes one small valid claim is the difference of a full tier — for life.

Source: 38 CFR § 4.25 — combined ratings table, 38 CFR § 4.26 — bilateral factor. Only the VA determines ratings; this is education, not a promise of outcomes.