VA math explained: how VA combines your disability ratings

VA math is the reason a 50% rating and a 30% rating don't make 80%. VA combines your ratings instead of adding them, using a method spelled out in federal regulation (38 CFR 4.25). Once you see how it works, your rating letter starts to make sense.

How does VA math work?

VA calls it the whole person method. Your first rating takes a bite out of 100%. Every rating after that bites only from what's left.

The regulation gives its own example. A 60% disability leaves a person 40% "efficient." A further 30% disability takes 30% of that remaining 40%, which is 12 more points. That leaves 28% efficiency, so the combined value is 72.

Here's the process step by step:

1. Sort your ratings from highest to lowest.
2. Combine the top two using VA's Combined Ratings Table (Table I in 38 CFR 4.25).
3. Combine that exact result with the next rating. Keep going until every rating is used.
4. Round the final number to the nearest 10. Values ending in 5 round up.

The fourth step trips people up. VA rounds once, at the end. A 65 in the middle of the math stays 65 until the last rating is combined.

Worked examples with 2026 pay

These examples use VA's rules and the pay rates that started December 1, 2025. They're for a veteran with no dependents.

Your ratings	Steps	Combined value	Final rating	Monthly pay
10, 10	10 + 10 = 19	19	20%	$356.66
40, 20	40 + 20 = 52	52	50%	$1,132.90
50, 30	50 + 30 = 65	65	70%	$1,808.45
60, 40, 20	60 + 40 = 76, then 76 + 20 = 81	81	80%	$2,102.15
30, 30, 10, 10	30 + 30 = 51, 51 + 10 = 56, 56 + 10 = 60	60	60%	$1,435.02
70, 50, 30, 10	70 + 50 = 85, 85 + 30 = 90, 90 + 10 = 91	91	90%	$2,362.30

Look at the 40 and 20. Sixty points of ratings end up as a 50% rating, because 52 rounds down. Now look at 50 and 30: a combined 65 rounds up to 70%. That single point of rounding is worth $675.55 a month at those two rates.

What is the bilateral factor?

The bilateral factor (38 CFR 4.26) is a small bonus for disabilities on both arms or both legs. "Arms" and "legs" mean the whole limb, so a right thigh and a left foot count as both legs.

VA handles it before any other combining:

1. Combine the bilateral ratings as usual.
2. Add 10% of that combined value. Added, not combined.
3. Treat the result as one rating and sort it in with the rest.

The regulation's own example uses ratings of 60, 20, 10 and 10, with the two 10s bilateral. The 10s combine to 19, and 10% of 19 is 1.9, so that pair becomes 21. Now the order is 60, 21, 20. The 60 and 21 combine to 68, and 68 and 20 combine to 74. The final rating is 70%, which pays $1,808.45 a month for a veteran alone.

Without the bilateral factor, those same four ratings also land at 74 and a 70% rating. So the bonus doesn't always change your rating. It matters most when your combined value sits just under a 5.

Why is my combined rating lower than I expected?

Mostly because of the math above, plus three habits worth knowing.

Small ratings shrink as you go. Once your combined value passes 90, another 10% rating adds about one point. In the 70, 50, 30, 10 example, the final 10% moves the value from 90 to 91.

The order is always highest first. Listing your ratings differently won't change the result, because VA sorts them anyway.

A 0% rating adds nothing to the combined number.

VA.gov explains the same rules in plain words on its ratings page. It also notes that combining keeps the total from ever going over 100%.

Check your own numbers

Put your individual ratings into our VA combined rating calculator. It shows each step of VA math, applies the bilateral factor if you enter ratings for both arms or both legs, and gives you the rounded rating.

Then take that rating to the VA disability pay calculator. Add your spouse, children and dependent parents to see your monthly amount. Rates change every December 1, so check back when the new table comes out.

If your rating letter shows a combined rating that doesn't match the math, VA's decision letter lists each condition and its percentage. Run them through the steps above before you call, and check the rounding step first.