Discount Calculator
More than a plain percent-off tool. Switch between four modes: a percentage discount, a fixed dollar amount off, working backward to the original price, or adding tax on top of the discounted price.
Your result will appear here
Choose a mode, enter your numbers, then click calculate.
More than percent off
Looking for just a quick percent-off number? Use our simpler Percent Off Calculator. This Discount Calculator is the broader version — four modes, including a fixed dollar amount off, a reverse solve for the original price, and tax applied after the discount.
Quick Answer
For a percentage: Discount = Original Price x (Percent Off / 100), and Final Price = Original Price - Discount. A $120 jacket at 25% off has a $30 discount and a $90 final price. This tool also handles a fixed amount off, reverse-solves the original price from a sale price, and adds tax on the discounted amount.
How It Works: Formula & Variables
Discount = Original × (Percent Off / 100) · Final = Original − Discount
- Percent off
- Discount = Original × (Percent / 100); Final = Original − Discount.
- Fixed amount off
- Final = Original − Discount($); the equivalent percent off is Discount($) / Original × 100.
- Reverse (find original)
- Original = Sale Price / (1 − Percent Off / 100).
- Tax after discount
- Total = Final Price × (1 + tax rate / 100), with tax charged on the discounted price.
Source: our own Percent Off Calculator, which documents the base percent-off math.
Worked Examples
Example 1: percent off
A $120 jacket at 25% off has a discount of $120 × 0.25 = $30, for a final price of $90.
Example 2: reverse-solve the original price
A $75 sale price at 25% off means the original was $75 / (1 − 0.25) = $75 / 0.75 = $100.
Example 3: stacked discounts are not additive
An $84.99 item at 40% off drops by $84.99 × 0.40 = $33.996, to $50.99. A further 10% off at the register takes $50.99 × 0.10 = $5.10 more, for a final price of $45.89. That 40% and 10% do not add up to 50% off — each discount works on the price left after the one before it.
Key Concepts
Percent depends on the price, a fixed amount doesn't: $30 off is always $30, but 25% off saves more the pricier the item.
Reverse math needs division, not subtraction: To recover an original price you divide by (1 minus the discount), which is why the original is always higher than a naive add-back would suggest.
Tax lands on the discounted price: Discount first, then tax on what's left — that ordering keeps the total honest.
Common Mistakes
Adding discount percentages together: 40% off plus 10% off is not 50% off, because the second discount applies to the already-reduced price.
Confusing the final price with the discount amount: What you save and what you pay are two different numbers.
Taxing the original price instead of the discounted one: Applying tax before the discount inflates the total.
Frequently Asked Questions
It means you pay 75% of the original price. The discount is 25% of the price, and what's left is the three-quarters you actually hand over.
Divide the sale price by (1 minus the discount as a decimal). A $75 sale price at 25% off means $75 divided by 0.75, which is a $100 original price.
No. The second discount comes off the already-reduced price, not the original. So 40% off and then 10% off is not 50% off — it works out to less, because the 10% is taken from a smaller number.
Usually after. The discount comes off first, and the tax or VAT is then calculated on the reduced price, not the original.
A fixed amount comes straight off the price — $30 off is $30 off no matter the price. A percentage depends on the original price, so the same percent saves you more on a pricier item.
Divide the discount amount by the original price and multiply by 100. A $30 discount on a $120 item is 30 / 120 x 100, which is 25% off.