A discount calculator answers the two questions every sale tag raises: how much money comes off, and what do you actually pay? Enter the original price and the percentage off, and this tool returns both figures instantly — no mental arithmetic at the checkout.
How It Works
The calculation is two lines long. The saving is the listed price multiplied by the discount percentage. The final price is the listed price minus that saving. That is all the tool does — which is exactly why it is reliable for checking whether a retailer's "sale price" matches the advertised percentage, comparing two competing offers, or sanity-checking a receipt.
The Formulas
Input Parameters
| Parameter | Unit | Description | |---|---|---| | Original Price | Currency | The full price before any discount; must be zero or more. | | Discount | % | The percentage off, between 0% and 100%. |
Worked Example
A jacket is listed at $150 with 30% off.
- Saving: 45**.
- Final price: 45 = $105.
A second quick check: an 12.75 and costs $72.25. If the register shows anything else, either a different percentage was applied or another charge has been added — and now you know to ask.
Stacked Discounts
Retailers sometimes layer offers — 20% off, then an extra 10% off at the register. Stacked discounts do not add: each applies to the already-reduced price. Run this calculator twice to model them. A 160; a further 10% off 144**. A single 30% discount would have given $140, so the stacked offer is effectively 28% off — four dollars less generous than it sounds. The general rule: multiply the survival factors (0.80 × 0.90 = 0.72) rather than adding the percentages.
Comparing Offers
Percentages mislead when the starting prices differ. A 150; a 153. The smaller discount on the cheaper item loses. Always compare final prices — the second output of this tool — never the percentages or even the savings alone.
Discounts and Tax
Discounts are normally applied before sales tax, GST or VAT: the tax is charged on the discounted price. So work out the discounted price here first, then apply tax to that amount if you need the full checkout total. To run the tax step, or to reverse a percentage (for example, finding the pre-discount price from a sale price), use the Percentage Calculator — divide the sale price by (1 − discount ÷ 100): a 70 ÷ 0.70 = $100.
Common Mistakes
- Adding stacked percentages. Covered above: 20% + 10% off is 28% off, never 30%.
- Confusing "percent of" with "percent off." Paying "70% of the price" is a 30% discount. Enter 30, not 70.
- Trusting an inflated original price. A discount is only as real as the price it starts from. The calculator faithfully computes from the figure you enter, so check the "was" price against what the item normally sells for.
- Buy-one-get-one-free arithmetic. BOGO on two equal items is a 50% discount on the pair: enter the combined price of both items with 50% to see the effective cost per item.
Frequently Asked Questions
How do I calculate 20% off a price?
Enter the price and 20 as the discount. For example, 20% off 16, giving a final price of $64. Mentally, 20% is one-fifth: divide the price by 5 and subtract.
What discount is a buy-one-get-one-free deal?
Fifty percent off the total for the pair, assuming both items cost the same. If the second item is cheaper, the effective discount on the combined price is less than 50%.
How do I find the original price from a sale price?
Divide the sale price by what remains after the discount: original = sale ÷ (1 − discount ÷ 100). A 100 original. This tool calculates forward (price and discount to sale price); the Percentage Calculator handles reverse percentages.