VA Bilateral Factor Calculator
When partial disability affects both arms, both legs, or paired skeletal muscles, 38 CFR 4.26 adds 10% of the paired ratings' combined value — it does not add 10% to your final rating.
What this tool cannot decide: whether your conditions actually qualify as paired extremities or paired muscles is a VA rating decision. Mark a pair only if you believe both sides are compensably rated for a paired condition. This tool models the math once you have marked the pair; it does not diagnose or rate a condition.
How 4.26 works, in order
- Combine the qualifying paired ratings as usual under 4.25.
- Add 10% of that combined value (not combined — added), and round to the nearest whole number. Example from the regulation: two 10% ratings combine to 19, plus 1.9 = 20.9, carried forward as 21.
- Treat that subtotal as one disability and combine it with all other ratings, greatest first.
- Four extremities: if both upper and lower pairs qualify, combine all four-extremity ratings in severity order first, then add 10% of that combined value (4.26(b)) — one subtotal, not two.
- Exception: if including a bilateral group would lower the combined evaluation, that group is removed from the bilateral calculation and its ratings are combined separately, to get the evaluation most favorable to the veteran (4.26(d)). This calculator tests that automatically and tells you when it fires.
Worked example from the regulation
Ratings of 60%, 20%, 10% and 10%, with the two 10% ratings bilateral: the pair combines to 19, the factor gives 21, and the order becomes 60, 21, 20. Combining gives 68, then 74, which converts to a 70% final rating. That example is in the test suite.