20/64 as a Decimal 0.3125 20/64 = 0.3125 = 31.25% Copy 20/64 = 0.3125 = 31.25%. Simplified: 5/16. Formula Used20 ÷ 64 = 0.3125 Frequently Asked Questions What is 20/64 as a decimal?0.3125.What is 20/64 as a percentage?31.25%.