30/100 as a Decimal 0.3 30/100 = 0.3 = 30% Copy 30/100 = 0.3 = 30%. Simplified: 3/10. Formula Used30 ÷ 100 = 0.3 Frequently Asked Questions What is 30/100 as a decimal?0.3.What is 30/100 as a percentage?30%.