3/15 as a Decimal 0.2 3/15 = 0.2 = 20% Copy 3/15 = 0.2 = 20%. Simplified: 1/5. Formula Used3 ÷ 15 = 0.2 Frequently Asked Questions What is 3/15 as a decimal?0.2.What is 3/15 as a percentage?20%.