What is 3% of 90? 2.7 3% of 90 Copy 3% of 90 = 2.7. Formula UsedResult = (3 ÷ 100) × 90 = 2.7 Frequently Asked Questions What is 3% of 90?2.7. (3 ÷ 100) × 90 = 2.7.How to calculate 3%?Multiply by 0.03 (or multiply by 3 then divide by 100).