Discount Calculator
With original price 80 usd, discount 25 percent, second discount at the till 20 percent, sales tax 0 percent, discount comes to $48.00 — sale price. It is reached in 8 steps, the last of which is 60 - 12, and each one is printed on the page with its numbers filled in. The formula is the one published by FTC, not an approximation fitted to it.
The price after a discount, the amount saved, and what a second discount stacked on the first actually comes to — which is never the two rates added together.
Formula and sources checked · How we check
Original price 80, Discount 25, Second discount at the till 20
$48.00
Sale price for the example below. Editing a field recomputes the calculator below; this figure holds the answer the page was loaded with.
It is written into the HTML rather than drawn by a script, so a search engine reading this page without running JavaScript still finds an answer.
- First discount saves
80 * 25 / 100$20- Price after the first discount
80 - 20$60- Second discount saves
60 * 20 / 100$12- Price after both
60 - 12$48- Total saved
80 - 48$32- Effective discount
32 / 80 * 10040- Sales tax on the sale price
48 * 0 / 100$0- Total at the till
48 + 0$48
Worked example
An $80 jacket at 25% off is $60. A further 20% at the till takes $12 off that, not $16, so it comes to $48 — a total saving of $32, which is 40% of the original price and not the 45% the two rates suggest when added.
How to work it out yourself
- 1.Apply discounts one after another, never added together. Two rates stack multiplicatively: 25% then 20% leaves 0.75 × 0.80 = 60% of the price, which is 40% off rather than 45%.
- 2.Check what the second discount applies to. "Extra 20% off sale prices" means off the reduced price; "20% off everything" at the same time as a sale sometimes means off the original, and the difference is real money.
- 3.Add sales tax last. Tax is charged on what you actually pay, so a discount reduces the tax with it — which is why a coupon is worth slightly more than its face value.
Effective discount when two stack
| Second discount at the till (percent) | Sale price | Price after both | Effective discount |
|---|---|---|---|
| 0 | $60.00 | $60 | 25 |
| 10 | $54.00 | $54 | 32.5 |
| 15 | $51.00 | $51 | 36.25 |
| 20 | $48.00 | $48 | 40 |
| 30 | $42.00 | $42 | 47.5 |
| 50 | $30.00 | $30 | 62.5 |
The formula
- First discount saves
80 * 25 / 100 - Price after the first discount
80 - 20 - Second discount saves
60 * 20 / 100 - Price after both
60 - 12 - Total saved
80 - 48 - Effective discount
32 / 80 * 100 - Sales tax on the sale price
48 * 0 / 100 - Total at the till
48 + 0
Source: FTC — guides against deceptive pricing, 16 CFR 233, NIST Handbook 130 — uniform pricing and price verification regulation
Questions people actually ask
- Is 25% off then 20% off the same as 45% off?
- No — it is 40% off. The second discount applies to the reduced price, so you keep 75% and then 80% of that: 0.75 × 0.80 = 0.60. Stacked discounts are always worth less than the sum of their rates, and the gap grows as the rates do.
- How do I calculate a percentage off?
- Multiply the price by the discount and subtract, or multiply by what is left directly. 25% off $80 is $80 × 0.75 = $60. The second form is fewer steps and is the one to use when discounts stack.
- What discount gets me to a target price?
- One minus the target divided by the original. To get an $80 jacket to $50 you need 1 − 50/80 = 37.5% off. Enter that here and the arithmetic confirms it.
Related
- Percent Off CalculatorThe sale price after a discount, after a second discount stacked on it, and after tax — with what you actually saved.
- Sales Tax CalculatorTax and total from a pre-tax price, plus the reverse — the pre-tax price hidden inside a total you already paid.
- Percentage CalculatorWhat X% of a number is, plus the discounted price, the marked-up price and the remainder.
- Margin and Markup CalculatorMargin and markup from cost and price — the two are not the same number, and the page shows both every time.
- VAT CalculatorValue added tax added to a net price or stripped out of a gross one, with the divisor that makes the second case work and the rate for every EU and UK band.
- Salary CalculatorPay converted between every period — hourly, daily, weekly, biweekly, semi-monthly, monthly and annual — with unpaid holidays and days off taken out.
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