VA Bilateral Factor Explained — How It Increases Your Combined Rating

What Is the Bilateral Factor?

The bilateral factor is an adjustment applied to VA combined ratings when a veteran has a ratable disability affecting paired extremities or organs — both arms, both legs, both hands, both feet, both knees, both hips, or both ears. The logic is that losing function on both sides of the body has a combined effect greater than simply adding the two ratings together.

Under 38 CFR § 4.26, the bilateral factor works like this: before the combined ratings formula is applied to bilateral conditions, the ratings for those paired conditions are added together and then increased by 10%. That increased combined number then gets run through the standard combined ratings calculation along with all other disabilities.

The Math — Step by Step

Let's say you have a 10% rating for your right knee and a 10% rating for your left knee. Here's how the bilateral factor is applied:

In this example, the bilateral factor effectively turns two 10% ratings into a 22% starting point rather than 19% (which is what straight combination math would give). That 3% difference, when rounded and combined with other ratings, can push a veteran from one rating tier to the next.

What Qualifies for the Bilateral Factor?

The bilateral factor applies to paired extremities and organs under 38 CFR § 4.26. Qualifying combinations include:

• Both knees — extremely common among veterans
• Both hips
• Both ankles / feet
• Both shoulders
• Both elbows / wrists / hands
• Both ears — bilateral hearing loss is the most commonly rated condition in the VA system
• Both eyes — visual acuity conditions in both eyes

The conditions on each side don't have to be identical. A veteran with a right knee at 10% (limited flexion) and a left knee at 20% (instability) still qualifies for the bilateral factor — both knees are affected, and the law doesn't require symmetry.

What Does NOT Qualify

• Conditions that aren't paired — a single knee, a single ear, one shoulder
• Internal organs that aren't "extremities" — bilateral kidney disease, for example, is not subject to the bilateral factor (it's rated under a different system)
• Mental health conditions — PTSD, depression, and other mental health ratings don't use the bilateral factor
• Tinnitus — even though it affects both ears, tinnitus is rated as a single condition under Diagnostic Code 6260, not bilaterally

A More Complex Example

Say you have: right knee 20%, left knee 10%, and PTSD 50%. Here's the correct calculation:

That's the difference between $1,395/month and $1,759/month — or roughly $4,368/year, tax-free, every year the bilateral factor is correctly applied.

How to Check If the VA Applied the Bilateral Factor Correctly

Your rating decision letter should show each condition rated separately and then the combined calculation. If you have bilateral conditions and the VA didn't mention the bilateral factor in your decision, it may not have been applied. You can:

1. Request your C-file to see the actual rating worksheet
2. Compare your combined rating to what the math should produce with the bilateral factor
3. If the bilateral factor wasn't applied or was applied incorrectly, file a supplemental claim citing 38 CFR § 4.26 as the basis for a corrected calculation

This is a technical argument — the kind of thing a VA attorney or accredited claims agent catches quickly. If you suspect your rating math is off, a professional review of your decision letter is worthwhile.