Discount Calculator

What this calculator does

This calculator works out the final price of an item after discounts. You enter an original price and up to two percentage discounts, which are applied sequentially, plus an optional sales tax. The tool then shows the final price, the total amount saved and the effective discount percentage, along with a step-by-step breakdown of how the price changed at each stage. Results update live as you type, and every calculation runs locally in your browser.

Why you might need it

Shops love layered offers — a seasonal sale with an extra coupon on top, or a member discount combined with a clearance reduction. Those stacked percentages are easy to misjudge, and it is tempting to add them together, which overstates the saving. A discount calculator shows the real final price and the genuine effective discount, so you can compare offers honestly, check that a coupon was applied correctly at the till, or decide whether a promotion is actually worth it. Adding sales tax gives you the true out-the-door amount rather than just the shelf price.

How to use it

1. Enter the original price of the item.
2. Choose the currency for display.
3. Enter Discount 1 as a percentage.
4. Optionally enter Discount 2 — it stacks on top of the first discount. Leave it at 0% if there is only one discount.
5. Optionally enter a sales tax percentage, applied after the discounts.
6. Read the results: the final price is the headline, with the total saved and the effective discount alongside, plus a breakdown table. Copy the final price if you need it.

How it’s calculated

Each discount multiplies the running price by (1 − rate ÷ 100). The first discount is applied to the original price; the second is applied to the result of the first. So with discounts d1 and d2 the discounted price is price × (1 − d1/100) × (1 − d2/100). Sales tax is then added on top: final = discounted × (1 + tax/100). The amount saved is the original price minus the discounted price (before tax), and the effective discount is that saving divided by the original price, as a percentage. Discount percentages are clamped to the 0–100 range so an out-of-range entry never produces a nonsensical result.

Common pitfalls

The headline mistake is adding stacked discount rates together — they multiply, they do not sum, so the effective discount is always less than the total of the rates. Another is mixing up the order of tax and discounts: tax should come last, on the already-discounted price, otherwise the figures drift. Be careful too that a “discount” is genuinely off the original price and not off an inflated reference price. Finally, the effective discount is measured before tax, so do not compare it against a tax-inclusive total.

Tips

To compare two offers, model each as a separate set of discounts and look at the effective discount percentage — that is the fair basis for comparison. If a promotion advertises a single combined percentage, enter it as Discount 1 and leave Discount 2 empty. Use the breakdown table to verify each step matches what a receipt shows. Because the tool is instant and private, you can test different discount and tax combinations as quickly as you can type, and nothing you enter ever leaves your browser.