Free · Sales calculators 💸

Single-Discount Price, Savings & Reverse Calculation

Calculate a sale price, savings or discount percentage, or recover an original price from known sale details.

  • Formula & worked example
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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Results are estimates for planning and education. Confirm rates, taxes, fees, and legal requirements with the relevant institution or a qualified professional before making a financial decision.

Formula and method

A 20% discount on 250 saves 50 and leaves a sale price of 200, before taxes and other charges.

Sale price = original price × (1 − discount/100); savings = original price − sale price

Worked example

Enter these known values and leave the other values blank.

Price before discount
250 USD
Discount
20 %
Price after discount
200 USD
You save
50 USD

Assumptions and limitations

  • Original price, sale price and savings are nonnegative. The discount ranges from 0% through 100%.
  • The calculation applies one discount before taxes and other charges. Successive discounts must be applied to the reduced balance in sequence.
  • Internal decimal arithmetic retains fractional minor currency units; final checkout rounding can change the charged amount.
  • A 100% discount and zero sale price do not uniquely identify the original price. Zero original and sale prices do not uniquely identify a discount rate.

Common questions

Are two 20% discounts the same as 40% off?

No. Two successive 20% reductions leave 64% of the original price, equivalent to 36% off.

Can I find the discount from two prices?

Yes. Enter a positive original price and the reduced price. The difference divided by the original price gives the discount fraction.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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