27/64 as a Decimal 0.421875 27/64 = 0.421875 = 42.1875% Copy 27/64 = 0.421875 = 42.1875%. Formula Used27 ÷ 64 = 0.421875 Frequently Asked Questions What is 27/64 as a decimal?0.421875.What is 27/64 as a percentage?42.1875%.