Subtract a percentage from a number
Subtract X% from Y
What this calculator does
It reduces a base amount Y by X percent of Y and shows what is left—the sale price or net after the reduction. A “20% off” label means you pay 80% of the original; this tool does that calculation for any X and Y.
The discount is taken from the original each time. Stacking multiple percent-off steps (e.g. 20% then another 10%) is a different rule set; this calculator applies one stated percent to one base.
Formula
Y − (Y × (X ÷ 100))
Factored form: Y × (1 − X ÷ 100). The amount removed is Y × (X ÷ 100), which you can verify with What is X% of Y?.
Worked example
Subtract 17.5% from 120: 120 × 0.175 = 21; 120 − 21 = 99.
Common questions
- How do you subtract a percentage from a number?
Remove X% of Y from Y: Y − (Y × X ÷ 100), same as Y × (1 − X ÷ 100).
- What is 20% off 100?
80. 20% of 100 is 20; 100 − 20 = 80.
- How is this different from percent change?
Percent change compares two numbers you already have. Here you apply a stated discount rate to one price to get the sale price.
- Do I add tax before or after a discount?
Often tax is calculated on the discounted price, but rules vary. Subtract the discount first, then use Add % on that total—verify local law.
- What does “10% off” mean?
You pay 90% of the original. The store removes 10% of the original price from the price.
- Can I stack two discounts (e.g. 20% then 10% off)?
This tool does one step. Stacked promos apply the second percent to a new base; that is not the same as adding the percents. Run the first discount, then use the result as Y for the second if needed.