40/64 as a Decimal 0.625 40/64 = 0.625 = 62.5% Copy 40/64 = 0.625 = 62.5%. Simplified: 5/8. Formula Used40 ÷ 64 = 0.625 Frequently Asked Questions What is 40/64 as a decimal?0.625.What is 40/64 as a percentage?62.5%.