Calculate& Decide

Everyday Math calculator

Discount Calculator

This calculator subtracts a percentage discount from the original price, then applies optional tax to the discounted subtotal.

Updated · Inputs stay in your browser

Enter your values

Choose the symbol used to display amounts.
Price before discount.
Percentage taken off.
Enter 0 when no tax applies.

Your values stay on this device. Nothing is sent to Calculate & Decide unless you deliberately use your device's share feature.

What this result means

This calculator subtracts a percentage discount from the original price, then applies optional tax to the discounted subtotal. The results panel explains the main number and the quantities that produced it, so you can check whether the estimate answers your real question.

Formula used

Discount = Original price × discount rate. Final price = (Original price − discount) × (1 + tax rate).

Step-by-step calculation

  1. Validate every required value and reject values outside the stated field limits.
  2. Convert rates and time periods to the units required by the formula.
  3. Calculate with full JavaScript number precision; do not round intermediate values.
  4. Round only the displayed result and explain the practical meaning.

Worked example

A $120 item at 25% off saves $30. With 8% tax on the $90 subtotal, tax is $7.20 and the final price is $97.20.

Assumptions and limitations

  • One percentage discount is applied to the original price.
  • Tax is applied after the discount.
  • Shipping, fixed coupons, and location-specific tax rules are excluded.

How to use this calculator

  1. Choose a currency symbol when the tool uses money.
  2. Enter values in the units shown beside each field.
  3. Select Calculate, then read both the main result and interpretation.
  4. Change one uncertain input at a time to understand sensitivity.
  5. Use Copy result or Share only when you choose to move the result outside this page.

Common mistakes

  • Adding the discount percentage to the tax percentage.
  • Applying tax to the original price when local rules tax the discounted subtotal.
  • Treating successive discounts as one combined sum.

Frequently asked questions

Can tax be zero?

Yes. Enter zero to calculate only the discounted price.

Does 20% off twice equal 40% off?

No. Successive discounts apply to different bases; this calculator models one discount.

Can a discount exceed 100%?

No. This tool limits the discount to 100%.

Methodology and sources

Formula definitions and edge-case behavior are documented on our Methodology page. No external data is fetched by this calculator.

See the site-wide calculation methodology and editorial standards. Formula errors can be reported through the error-reporting instructions.

Published and reviewed .