What is 9% of 40? 3.6 9% of 40 Copy 9% of 40 = 3.6. Formula UsedResult = (9 ÷ 100) × 40 = 3.6 Frequently Asked Questions What is 9% of 40?3.6. (9 ÷ 100) × 40 = 3.6.How to calculate 9%?Multiply by 0.09 (or multiply by 9 then divide by 100).