How to check the Bilateral Factor (38 CFR § 4.26) on your VA rating — arms, legs and paired muscles
The bilateral factor (38 CFR § 4.26) applies when you have service-connected disabilities at a compensable level (10% or more) in both arms, both legs, or paired skeletal muscles. VA combines the ratings for the two sides, adds 10 percent of that combined value, and only then combines the result with your other ratings. It is a small boost, so it changes your final rounded rating only some of the time — but when it does, it can move you up a full 10% level. This guide shows the math, how to check your decision letter, and how to ask VA to correct a missed bilateral factor.
What you'll need
- Your VA rating decision letter listing every service-connected condition and its percentage
- The Combined Ratings Table (38 CFR § 4.25) and the bilateral factor rule (38 CFR § 4.26)
- A calculator (or VA's disability rating calculator, if it shows a bilateral option)
- VA Form 20-0996 (Higher-Level Review) if you are within one year of the decision
- A free accredited representative (county veterans service officer or VSO) to check the math with you
Step-by-step
Step 1: Find conditions that count as "bilateral"
Under 38 CFR § 4.26 the factor applies to compensable disabilities of both arms, both legs, or paired skeletal muscles. "Arms" and "legs" mean the whole upper and lower extremities, so the two sides do not have to match: a right knee and a left ankle, or a right shoulder and a left wrist, are a bilateral pair. Each side must be rated at a compensable level. The factor does NOT apply to eyes, hearing loss or tinnitus (those are rated under their own rules — tinnitus is a single rating no matter how many ears), the spine, or internal organs.
Step 2: Do the math the way 38 CFR §§ 4.25–4.26 describe
(1) Combine the bilateral ratings with each other using the Combined Ratings Table (the higher rating first, then the next rating applied to what is left). (2) Add — not combine — 10 percent of that value. (3) Combine the result with your other ratings in order of severity. (4) Round only the final number to the nearest 10% (5 rounds up). EXAMPLE THAT CHANGES THE RESULT: right knee 20%, left knee 10%, PTSD 50%. Without the bilateral factor: 50, then 20 of the remaining 50 = 60, then 10 of the remaining 40 = 64, which rounds to 60%. With it: the knees combine to 28, plus 10% of 28 (2.8) = 30.8; then 50 plus 30.8% of the remaining 50 = 65.4, which rounds to 70%. EXAMPLE THAT DOES NOT: right knee 10%, left knee 10%, PTSD 70%. Without: 70 → 73 → 75.7, rounds to 80%. With: knees 19 plus 1.9 = 20.9; 70 plus 20.9% of 30 = 76.3, still 80%.
Step 3: Check your decision letter
Find the list of your service-connected conditions and the combined rating. Some letters mention the bilateral factor; many simply state the combined rating. Recalculate using Step 2. If your result matches VA's combined rating, nothing needs fixing. If your result is a higher rounded rating, VA may have missed the bilateral factor. Ask a county veterans service officer or other accredited representative to double-check before you file — it is free.
Step 4: Choose how to ask VA to correct it
WITHIN ONE YEAR of the decision: request a Higher-Level Review on VA Form 20-0996 and explain that the bilateral factor under 38 CFR § 4.26 was not applied, showing your calculation. No new evidence is needed for a math error. AFTER ONE YEAR: you can ask VA in writing to revise the decision for clear and unmistakable error (CUE), identifying the specific error and how it changed the outcome. A CUE request has no deadline; if it is granted, the correction takes effect as if the original decision had been right. A representative can prepare either request for you.
Step 5: Watch for the corrected decision
If VA agrees, you will receive a new decision with the corrected combined rating, and any past-due amount is paid separately. Recheck the math whenever VA adds or changes a rating — a new condition on the opposite arm or leg can create a bilateral pair that did not exist before.
Critical tips
- The bilateral factor adds 10 percent of the combined bilateral value (for example 2.8 points on a 28), not 10 points to your overall rating.
- It matters most when your unrounded total is close to the next rounding line — for example 64 versus 65.
- Right and left sides do not have to be the same joint: any compensable condition of each arm (or each leg) counts.
- Tinnitus, hearing loss and vision are not part of the bilateral factor.
- A Higher-Level Review must be requested within one year of the decision; a CUE request has no deadline but requires a clear, outcome-changing error.
- County veterans service officers and VSO representatives check rating math for free.