3/12 as a Decimal 0.25 3/12 = 0.25 = 25% Copy 3/12 = 0.25 = 25%. Simplified: 1/4. Formula Used3 ÷ 12 = 0.25 Frequently Asked Questions What is 3/12 as a decimal?0.25.What is 3/12 as a percentage?25%.