6/15 as a Decimal 0.4 6/15 = 0.4 = 40% Copy 6/15 = 0.4 = 40%. Simplified: 2/5. Formula Used6 ÷ 15 = 0.4 Frequently Asked Questions What is 6/15 as a decimal?0.4.What is 6/15 as a percentage?40%.