The VA uses a formula — not addition — to combine disability ratings. A 50% + 30% = 65%, not 80%. Step-by-step examples, the bilateral factor, and how to calculate your combined rating.
If you have more than one service-connected disability, your overall rating isn't what you'd get by adding the individual ratings. The VA uses a "combined ratings" formula — often called "VA math" — that works fundamentally differently from regular addition. Understanding how it works helps you anticipate your combined rating and make strategic decisions about which conditions to claim.
The core principle of VA math is that each disability is applied to the remaining "whole" part of your body. Imagine you start at 100% able-bodied. Your highest-rated condition reduces that percentage. Then your next-highest condition is applied only to what's left. Each subsequent condition reduces a smaller and smaller remainder.
Here's a concrete example. Say you have three conditions rated at 50%, 30%, and 20%. Start with 100% whole. Apply 50% — you're now 50% disabled and 50% remaining. Apply 30% to the remaining 50% — that's 15%, bringing you to 65% disabled with 35% remaining. Apply 20% to the remaining 35% — that's 7%, bringing you to 72% disabled. Round to the nearest 10%: your combined rating is 70%.
If you simply added 50 + 30 + 20, you'd get 100%. But VA math gives you 70%. This is why veterans are often surprised by their combined rating — it's almost always lower than the sum of individual ratings. The math makes a kind of logical sense (you can't be more than 100% disabled, and each condition affects a person who's already partially disabled), but it feels counterintuitive when you're the one receiving the rating.
The rounding rules are critical. The VA rounds to the nearest 10%, and the difference between rounding up and down can be a significant amount of monthly compensation. A combined raw score of 75% rounds up to 80%. A raw score of 74% rounds down to 70%. The difference in monthly compensation between 70% and 80% is hundreds of dollars per month for a veteran with dependents. This is why many VSOs carefully analyze which conditions to claim to maximize the chance of crossing a rounding threshold.
The bilateral factor provides a small boost when you have conditions affecting both sides of your body — for example, bilateral knee conditions or bilateral hearing loss. The VA adds 10% of the combined value of the bilateral conditions to the overall calculation. It's a small adjustment, but it can be enough to push a rating over a rounding threshold.
Understanding VA math helps you have realistic expectations about your combined rating and helps your VSO strategize about which claims to prioritize. Vet Debrief's free briefing tool estimates your potential benefits based on your current or expected rating level.
VA math reflects the principle that each disability affects a person who is already partially disabled. You can't be more than 100% disabled, so each additional condition is applied to the remaining "whole" percentage rather than added to the total. This prevents combined ratings from exceeding 100%.
The VA rounds the final combined rating to the nearest 10%. A combined raw score of 75% rounds up to 80%, while 74% rounds down to 70%. This rounding can mean a difference of hundreds of dollars per month in compensation, which is why strategic claim planning matters.
The bilateral factor is a small boost applied when you have conditions affecting both sides of your body — for example, bilateral knee conditions or bilateral hearing loss. The VA adds 10% of the combined value of the bilateral conditions to the overall calculation, which can help push a rating over a rounding threshold.
Your combined schedular rating caps at 100%. However, veterans rated at 100% may also qualify for Special Monthly Compensation (SMC) which provides additional payments above the 100% rate for specific severe conditions like loss of use of limbs or organs.
No. The VA always applies conditions from highest to lowest rating, regardless of the order they were rated. The final combined result is the same no matter what order the conditions were service-connected.