What is 50% of 80? 40 50% of 80 Copy 50% of 80 = 40. Formula UsedResult = (50 ÷ 100) × 80 = 40 Frequently Asked Questions What is 50% of 80?40. (50 ÷ 100) × 80 = 40.How to calculate 50%?Multiply by 0.5 (or multiply by 50 then divide by 100).