You have a 50% rating for one condition and a 30% for another. That’s 80%, right?
No. It’s 70%. And the reason why is the single most confusing thing in the entire VA disability system — a calculation so counterintuitive that veterans have nicknamed it “VA math.”
Why Ratings Don’t Add Up
The logic makes sense once you see it, even though the result feels wrong.
The VA doesn’t measure how disabled you are. It measures how much whole person you have left. Each additional rating is applied to what remains — not to the original 100%.
Working Through 50% + 30%
- Start at 100%. You begin as a whole person.
- Apply the highest rating first. A 50% disability takes 50 points. You have 50% remaining.
- Apply the next rating to what’s left. 30% of the remaining 50 is 15 points — not 30.
- Add the losses. 50 + 15 = 65% combined.
- Round to the nearest 10. 65% rounds up to 70%.
Same math, different starting point: a 60% and a 20% combine to 68%, which rounds to 70% — not 80%.
What Combinations Actually Produce
| Your Ratings | Simple Addition Would Say | Actual Combined Rating |
|---|---|---|
| 50% + 30% | 80% | 70% |
| 60% + 20% | 80% | 70% |
| 30% + 30% | 60% | 50% |
| 70% + 30% | 100% | 80% |
| 10% + 10% | 20% | 20% |
The official combined ratings table lives in 38 CFR § 4.25, the actual federal regulation. Ratings are always ordered from most to least severe before combining.
Why Rounding Matters More Than You’d Think
Because the final figure rounds to the nearest 10%, small differences near a boundary have outsized consequences.
A combined value of 64% rounds down to 60%. A combined value of 65% rounds up to 70%. That single point can mean a meaningful difference in monthly compensation — and it can determine whether you cross a threshold that unlocks other benefits entirely.
This is why an additional low rating that seems trivial is sometimes worth pursuing. A 10% rating added to an existing 68% can push you over a line.
The Diminishing Returns Problem
Once you understand the formula, an uncomfortable pattern emerges: the higher your rating already is, the less each new rating is worth.
A first 30% rating takes 30 full points. A 30% rating added to an existing 70% takes only 9 points, because it’s applied to the 30% you have left. The same condition, the same severity, worth a third as much.
This is why veterans at 80% or 90% sometimes find it enormously difficult to reach 100% through the schedule alone — each additional claim moves the needle less than the last. It’s also why TDIU, covered below, exists as an alternative route.
None of that is a reason to stop filing. It’s a reason to understand what a new claim will realistically do before you pin your expectations on it.
The Bilateral Factor
Here’s a rule most veterans have never heard of, and it can add rating you’re entitled to.
If you have disabilities affecting both arms, both legs, or paired skeletal muscles, the VA combines those paired ratings first and then adds an extra 10% of that figure before combining with everything else.
The reasoning is practical: losing function in both knees is more disabling than losing it in one, because there’s no good side to compensate with. The bilateral factor is the system acknowledging that.
It applies automatically when the VA recognizes the conditions as bilateral — but only if both sides are actually service-connected and rated. If you have a rated left knee and an unrated right knee with the same problem, filing for the second side may be worth more than the second rating alone suggests.
TDIU: 100% Pay Without a 100% Rating
Total Disability based on Individual Unemployability is one of the most under-claimed benefits in the system.
TDIU pays at the 100% rate for veterans who can’t hold substantially gainful employment because of service-connected conditions — even if their combined rating is below 100%.
The general schedular threshold is:
- One disability rated 60% or higher, or
- Two or more disabilities with at least one rated 40% or higher, combining to 70% or more.
And here’s where it connects back: the bilateral factor counts toward reaching that 70% threshold. For some veterans, that 10% bump is the difference between qualifying for TDIU and not.
What a Rating Actually Determines
The percentage isn’t only a compensation figure. It’s a key that unlocks other things, which is why crossing a threshold can matter more than the monthly difference alone.
- Monthly compensation, which increases at each 10% step and is higher for veterans with dependents at 30% and above.
- VA health care priority group — covered in our guide to VA health care enrollment.
- The VA home loan funding fee exemption, which applies to veterans receiving compensation for a service-connected disability. See our VA home loan guide.
- State benefits. Oregon’s disabled veteran property tax exemption is keyed to a qualifying rating.
- Dependent education benefits through DEA, tied to certain ratings.
- Dental care eligibility. A compensable dental disability, or a 100% schedular or TDIU award, opens VA dental treatment — see our guide to the VA dental eligibility classes.
A veteran who reaches a threshold sometimes gains several of these at once, which is why the rounding boundary is worth more than it first appears.
Practical Takeaways
- Don’t dismiss small claims. A 10% rating can push a combined value across a rounding boundary.
- Claim both sides of paired conditions. The bilateral factor rewards it — and bilateral radiculopathy from a spine condition is the classic case, covered in our guide to how VA rates the back and spine.
- Know the ceilings before you plan around a number. Some conditions cap out low — tinnitus maxes at 10% for both ears combined, and sleep apnea has no 10% or 20% level at all.
- Check whether you’re TDIU-eligible if you’re at 70% combined and struggling to work. Our guide to TDIU and the rule that groups separate disabilities into one covers the thresholds in detail.
- Understand that later ratings are worth less in combined terms — the higher your existing rating, the smaller the effect of adding another.
- Don’t calculate it yourself and stop there. Free help is available.
That last point matters. An accredited representative can spot combinations and thresholds most veterans miss — see our guide to free VA claim help from service officers, and note that PACT Act presumptive conditions may add ratings you haven’t claimed.
Frequently Asked Questions
Why doesn’t 50% + 30% equal 80%?
Because each rating applies to the whole-person percentage remaining, not the original 100%. 30% of the remaining 50% is 15 points, giving 65%, which rounds to 70%.
How does the VA round combined ratings?
To the nearest 10%. A combined 64% becomes 60%; a combined 65% becomes 70%.
What is the bilateral factor?
An additional 10% added when disabilities affect both arms, both legs, or paired skeletal muscles, applied after those paired ratings are combined.
Can I get 100% pay without a 100% rating?
Yes, through TDIU, if service-connected conditions prevent substantially gainful employment and you meet the schedular thresholds.
Is it worth filing for a condition only worth 10%?
Often yes. Small ratings can push your combined value past a rounding boundary or help you reach a TDIU threshold.
Where is the official combined ratings table?
In federal regulation at 38 CFR § 4.25, which sets out how the VA combines multiple disability ratings.
Get a Second Set of Eyes
VA math is genuinely counterintuitive, and misunderstanding it leads veterans to leave claims unfiled. A free accredited service officer will run your numbers properly. Post 51 can point you toward one — call (541) 451-1351, or start with your county veteran service officer.