In simple terms, bilateral disabilities would be having an additional “bonus” from the VA to help compensate the fact that having a disability on one side of your body, say left knee, is more of a handicap if you should have a corresponding disability on the other lower extremity, than rating them completely separate. So 10% for left knee, 10% for right knee, plus an additional 10% (10+19=19 x 10%=1.9 Add the 1.9 to the 19 and the bilateral number for your knees is 21%. It helps a lot when you climb the disability claim ladder. (I believe this is correct without using a calculator that does bilateral.) Here’s where it gets a little wonky. I have s-c bilateral hearing loss by the VA and it is rated at 10%. What? If it is BILATERAL and I have hearing loss in both ears, why is it not 21% instead of 10%? Either the VA is using a different definition when talking about hearing loss, or my disability is miscalculated. Any comments welcome.