How VA Disability Ratings Actually Work

The VA treats disability as a measure of how much of your overall function remains, not as a simple deduction from 100. Think of it as starting with 100% of your full efficiency. Your highest-rated disability is applied first, and it reduces that efficiency by its percentage. Every additional rating is then applied to whatever efficiency is left, not to the original 100%.

Take a veteran with a 50% rating and a separate 30% rating, as a generic illustration of the mechanism. The 50% rating is applied first, leaving 50% of overall efficiency remaining. The 30% rating is then applied to that remaining 50%, not the full 100%, which works out to another 15 percentage points (30% of 50). Fifty plus fifteen equals a combined value of 65, not the 80 that simple addition would suggest. That combined value then gets rounded, as described below, to arrive at the rating that actually appears on a decision letter. This same logic underlies the VA's Combined Ratings Table, and it holds no matter how many separate ratings are being combined or in what order, since the math works out the same either way.

When a veteran has service-connected conditions affecting both sides of a paired set, such as both knees, both hands, or both arms, the VA applies something called the bilateral factor before those ratings get folded into the rest of the combined rating. The reasoning is that a disability affecting both members of a paired extremity has a greater overall impact than the same two conditions would if they affected unrelated body parts, so the standard combined-ratings math would understate it.

In practice, the VA first combines the ratings for the paired conditions using the same efficiency-based method described above, then adds an additional 10% of that combined value on top, before folding the result into the rest of the ratings. It's a narrow rule that only applies to specific paired body parts defined by regulation, but it can meaningfully change a combined rating for veterans with bilateral joint or limb conditions.

VA disability ratings are always issued in increments of 10. After all individual ratings have been combined using the efficiency method, with the bilateral factor applied where relevant, the resulting combined value gets rounded to the nearest multiple of 10. A combined value that lands exactly halfway between two increments rounds upward. That final, rounded number is the combined disability rating, and it's what drives compensation and most other eligibility determinations across the VA system.

Understanding this mechanism helps in a few concrete ways. It explains why a new secondary condition rated at 10% might barely move a combined rating if you're already at a high combined value, since it's only being applied to a shrinking remainder of efficiency. It also explains why the order conditions appear in on a decision letter doesn't change the outcome, even though it can look like it should.

If you're building a claim strategy around multiple conditions, running the numbers yourself before you file, rather than after a decision letter arrives, can save a lot of confusion. The VA Disability Rating Calculator walks through this exact step-by-step breakdown for your own combination of ratings. The VA Compensation Rates tool shows how a given combined rating translates into monthly compensation. And if you already have one service-connected condition, the Secondary Conditions Finder can help identify related conditions commonly connected to it, which is often how veterans end up combining multiple ratings in the first place.