Updated June 17, 2026
Try the Percentage Calculator
Instant answers for any percentage problem: find the percent, the part, or the whole in one click.
Sale Price = Original Price x (1 - Discount Percent / 100). So 20% off $80 is $80 x (1 - 0.20) = $80 x 0.80 = $64. The discount amount itself is Original Price x (Discount Percent / 100), in this case $80 x 0.20 = $16.
Quick formula summary
| What you want | Formula |
|---|---|
| Sale price after X% off | Original x (1 - X/100) |
| Amount saved | Original x (X/100) |
| Discount percentage | ((Original - Sale) / Original) x 100 |
How to take 20% off a price
Multiply the original by 0.80 (that is, keep 80%). $120 x 0.80 = $96. Or find 20% first ($120 x 0.20 = $24) and subtract: $120 - $24 = $96.
How to calculate 15% off
Find 10% (move the decimal left one place), then add half of that for 5%, and sum them. 15% of $60: 10% = $6.00, 5% = $3.00, so 15% = $9.00. Sale price: $60 - $9 = $51.
How to calculate 30% off
Multiply by 0.70. $50 x 0.70 = $35. Or find 10% ($5), multiply by 3 ($15), subtract from original: $50 - $15 = $35.
Finding the original price when you know the sale price
If an item costs $72 after a 20% discount, the original was $72 / 0.80 = $90. Use the Discount Calculator for any of these in a click, or see how to calculate percentage for the broader math behind it.
Try the Percentage Calculator
Instant answers for any percentage problem: find the percent, the part, or the whole in one click.