VA Disability Rating Calculator
How the VA Actually Combines Multiple Ratings
Most veterans assume disability ratings add up the way regular math does. If you're rated 40% for your back and 20% for your knee, it feels like that should be 60%. It isn't.
The VA doesn't add percentages. It looks at how much of your overall function each condition takes away, one at a time. Picture your health as a whole, 100% to start. The first rating reduces that whole by its percentage. The second rating then reduces what's left, not the original 100%.
So a 40% rating combined with a 20% rating doesn't equal 60%. It works out to 52%, which the VA then rounds to the nearest 10%, in this case 50%. This is often called "VA math," and it surprises almost everyone the first time they see their combined rating come back lower than they expected.
The Bilateral Factor: An Extra Boost for Paired Limbs
There's one place VA math actually works in your favor: paired limbs.
If you have compensable ratings on both sides of your body, both knees, both shoulders, both hands, the VA doesn't just combine those two ratings like normal. It combines them, then adds an extra 10% on top of that combined value before folding it in with your other conditions. The reasoning is straightforward: losing function in both knees limits you more than losing the same function in just one.
This step gets missed more often than any other part of a VA rating decision. If you have any bilateral condition, it's worth double-checking that this factor was actually applied.
Why 100% Gets Harder to Reach the Higher You Go
Because each new rating only applies to what's left of your remaining function, not your original 100%, every additional condition adds less than the one before it. A veteran with five different 20% ratings will never reach 100% through combination alone. This is normal, not a sign that something was calculated wrong.
This is exactly why an accurate rating on every condition matters. Missing a rating, or having a rating supported by weak or incomplete medical evidence, has an outsized effect near the higher end of the scale.
What If I Can't Work Because of My Conditions?
If your service-connected conditions prevent you from holding substantially gainful employment, you may qualify for Individual Unemployability (TDIU), which can pay at the 100% rate even if your combined schedular rating is lower. Eligibility depends on your specific ratings and work history, so this is worth discussing directly with the VA or an accredited representative.
Where a Nexus Letter Fits Into All of This
None of this math matters until a condition is actually service-connected. Before the VA can rate a disability at all, there has to be a documented medical link between your current condition and your time in service. That's what a nexus letter provides.
We write nexus letters personally, Dr. Kristopher Biegel and Dr. Elle Biegel, both licensed chiropractic physicians, review every case ourselves. We offer a free records review first, so you'll know whether we can support your claim before you pay anything.
Ready to Strengthen Your VA Claim?
Have questions?
Email us at nexus@nexusletternow.com for assistance.