Discount Calculator

A single percentage off a single price. That is deliberately all this tool does, and knowing what it does not do is more useful than knowing what it does.

Straightforward case first

A 249.00 item at 35% off:

• You save: 87.15
• Sale price: 161.85

Saving    = price × discount ÷ 100
Sale price = price − saving

The discount input is bounded at 0 to 100. Anything outside that range is rejected rather than producing a negative price, because a 120% discount is not a thing a shop can do.

Stacked discounts multiply, they do not add

This is the reason most people get a till receipt they were not expecting.

Take 100.00. Apply 20% off and you have 80.00. Apply a further 10% to that and you have 72.00 — a total reduction of 28%, not 30%. The second percentage is taken from the already-reduced figure, so each successive discount is worth less than its face value.

There is no second-discount field on this page. To model a stack, run the tool twice: take the sale price from the first pass and use it as the original price in the second. The order does not matter — 10% then 20% also lands on 72.00 — but the arithmetic does.

Percent off versus the price you pay

Two ways of stating the same offer:

Retail marketing states the first column because it is the larger number. Comparing two offers is easier in the second: an item at 40% off from one shop and 30% off from another are only comparable if the list prices match, which they frequently do not. Compare final prices, not percentages.

What this does not include

Tax. The calculation is entirely pre-tax. Where tax is added at the register, it is levied on the discounted price, so the saving is slightly larger than shown. Where tax is already inside the shelf price, the discount reduces both the net and the tax.

Shipping. A free-shipping threshold can make a smaller discount the better deal.

Coupon rules. Stacking is often prohibited outright, and a percentage coupon frequently excludes sale items, gift cards and specific brands.

The reference price. A percentage is only as meaningful as the price it is taken from. An "up to 70% off" banner typically applies to a handful of lines, and a discount from an inflated list price is not a saving. This tool takes the original price at face value; judging whether that price was ever real is your job.

Elsewhere on the site

To check whether a proposed discount still leaves a workable margin, use the profit margin calculator. To add tax to the discounted figure afterwards, use the sales tax calculator or the VAT calculator. For percentage arithmetic in other directions, use the percentage calculator.