What is 20% of 40?
20% of 40 is 8. Use the calculator below to change either number, or see related calculations.
Calculating 20% of 40: divide 20 by 100, then multiply by 40. The general formula is (X ÷ 100) × Y — works for any percentage and any number.
Round percentages like this are easy to estimate mentally and common in UK retail and tax. This base value sits in the everyday range — receipts, tips, small purchases.
How it works.
Formula: (X ÷ 100) × Y.
Step by step:
- Divide the percentage by 100: 20 ÷ 100 = 0.2.
- Multiply by the number: 0.2 × 40 = 8.
Worked examples
20% of 40 = 8 — the basic calculation: divide 20 by 100 (= 0.2), then multiply by 40.
20% of 40 as a tip on a small bill — if a service charge of 20% is added to a 40 item, the extra is 8.
20% off a 40-pound item — the discount saves 8; the sale price is £32.
Frequently asked questions
How do I calculate 20% of 40?
Divide 20 by 100, then multiply by 40. 20 ÷ 100 = 0.2; 0.2 × 40 = 8. The same formula works for any pair of numbers.
What is 20 percent of 40?
8. The full calculation: (20 ÷ 100) × 40 = 0.2 × 40 = 8.
What's the formula for any percentage of any number?
Divide the percentage by 100 to convert it to a decimal, then multiply by the number. The general formula is (X ÷ 100) × Y. The percentage calculator above uses this for any pair of values; results display to 4 decimal places.