18/100 as a Decimal 0.18 18/100 = 0.18 = 18% Copy 18/100 = 0.18 = 18%. Simplified: 9/50. Formula Used18 ÷ 100 = 0.18 Frequently Asked Questions What is 18/100 as a decimal?0.18.What is 18/100 as a percentage?18%.