What is 80% of 15? 12 80% of 15 Copy 80% of 15 = 12. Formula UsedResult = (80 ÷ 100) × 15 = 12 Frequently Asked Questions What is 80% of 15?12. (80 ÷ 100) × 15 = 12.How to calculate 80%?Multiply by 0.8 (or multiply by 80 then divide by 100).