What is 40% of 75? 30 40% of 75 Copy 40% of 75 = 30. Formula UsedResult = (40 ÷ 100) × 75 = 30 Frequently Asked Questions What is 40% of 75?30. (40 ÷ 100) × 75 = 30.How to calculate 40%?Multiply by 0.4 (or multiply by 40 then divide by 100).