Markdowns, coupons and stacked promotions are everywhere, and the math behind them is rarely obvious. The ChrysoKit Discount Calculator turns those numbers into something you can see at a glance, with no spreadsheet needed.
Why use it
Whether you are shopping, pricing your own products, or checking that a sale is what the sticker claims, a quick calculator beats mental arithmetic every time. It also catches the classic trick where two stacked discounts do not add up to the headline number.
How to use the Discount Calculator
- Enter the original price.
- Type the discount as a percentage, or as a fixed amount off.
- Read the final price and total savings instantly.
- Stack a second discount if the offer chains two together.
Features worth knowing
Percentage and flat amounts
Switch between a percentage off and a flat currency reduction without changing tools.
Stacked discounts
Apply a second discount on top of the first to mirror real promotions like '20% off, then extra 10% at checkout'.
Live results
All numbers update as you type. No submit button, no waiting.
Pro tips
- Two stacked discounts of 20% and 10% do not equal 30% off. They equal 28% off the original price. The calculator makes this obvious.
- Use the flat-amount mode for coupons phrased as 'X off' rather than 'X percent off'.
- Round only at the end. Rounding mid-calculation is how cents go missing.
Privacy first. The Discount Calculator runs entirely in your browser. Nothing you enter is sent to a server.
Open the Discount Calculator the next time a sale needs decoding. It is fast, accurate and works offline.
Open the tool: Discount Calculator →
Black Friday forensics: auditing a "70% off" weekend
Sales weekends are where discount arithmetic meets behavioural design, and walking a real shopping list through a calculator is an education in both.
Item one: headphones, "was 299, now 149... 50% off". A price-history check shows they sold at 189 for most of the autumn; the genuine discount against the prevailing price is 21%. The anchor price is not a lie exactly... they did list at 299 once... but the calculator's job here is computing the discount against the price you would actually have paid last month.
Item two: the stacking offer... 30% off, extra 15% with a code, plus 10% cashback. Intuition sums to 55%; the real cascade (0.70 x 0.85, then 10% back on the 59.5 paid) nets out near 46.5%. Still good... but every stacked offer overstates itself by construction, and knowing the true figure changes which of two competing deals wins.
Item three: "3 for 2" on consumables against a rival's flat 30% off. Per-unit arithmetic settles it: 3-for-2 is 33% off, but only if the third unit was genuinely wanted... a third one that expires unused converts the bargain into full price for two.
The weekend's audit habit in one sentence: convert every offer format... anchors, stacks, bundles... into a single per-unit price against the recent real price, and let that one number make the decision. Retail formats multiply; the arithmetic that defends against them does not change.