80% Off 100

80% off 100 = 20 (you save 80)

How to calculate 80% off 100

  1. Find the discount: 80% of 100 = 0.8 × 100 = 80.
  2. Subtract it from the price: 100 − 80 = 20.

Or in one step, multiply by the share you pay: 100 × 0.2 = 20.

Stacked discounts do not add up: an extra 10% off the sale price gives 18, which is 82% off in total, not 90%.

Frequently asked questions

What is 80% off 100?

The sale price is 20 and you save 80.

How do you calculate a percentage of a number?

Divide the percentage by 100 and multiply by the number: 15% of 80 = 0.15 × 80 = 12.

How do you find what percent one number is of another?

Divide the part by the whole and multiply by 100: 12 is 12 ÷ 80 × 100 = 15% of 80.