Discount Calculator
Final price after a discount, and how much you save.
Your figures
Result
How to use this tool
- Enter your own figures over the defaults — Original price, Discount.
- The answer updates as you type. There is no button, and nothing is sent anywhere.
- Change Discount on its own to see how much it moves the result — the worked example below shows exactly that.
Stacked discounts multiply rather than add. "30% off then 20% off" is 44% off in total, not 50%.
How it works
This takes 2 inputs — original price, discount — and returns you pay and you save. The whole calculation happens in this page as you type: there is no submit button, no request, and nothing stored.
Because it recalculates on every keystroke you can use it as a sensitivity test rather than a one-shot answer. Moving discount alone from 30 to 31 changes you pay from 84.00 to 82.80 — the worked example below sets that out in full.
A worked example
Worked through with the figures the page already has in it: original price of 120 and discount of 30 %, giving you pay of 84.00. These numbers come from running the calculator’s own code, not from being typed in here, so they cannot drift away from what you see on screen.
Starting from:
- Original price: 120
- Discount: 30 %
| Result | Value |
|---|---|
| You pay | 84.00 |
| You save | 36.00 |
What happens when one input moves
Holding everything else steady and changing Discount from 30 % to 31 % — one percentage point — moves the answer like this:
| Figure | 30 % | 31 % |
|---|---|---|
| You pay | 84.00 | 82.80 |
| You save | 36.00 | 37.20 |
That is usually the number worth arguing over: it is easier to move than the headline amount, and the difference compounds across the whole term.
Discount Calculator — frequently asked questions
How do I calculate a discount?
Multiply the price by the discount percentage to get the saving, then subtract it. 30% off £120 saves £36, leaving £84.
How do stacked discounts work?
They compound. 30% then 20% leaves 0.7 × 0.8 = 0.56 of the original price, so 44% off — not 50%.
What about tax?
Discount is normally applied before sales tax. Use the sales tax calculator for the final figure.
Is this calculator free?
Yes, with no account, no limits and no data collection. It runs entirely in your browser.
Should I rely on this for a financial or medical decision?
No. It is a planning estimate built on standard formulas and stated assumptions. For decisions that matter, speak to a qualified professional who can account for your full circumstances.
How accurate is the Discount figure?
The arithmetic is exact. With the defaults on this page — original price 120, discount 30 % — it returns you pay of 84.00. What limits accuracy is the assumptions, not the maths: change discount to 31 % and the same formula gives 82.80. Treat it as a well-founded estimate, not a quotation.
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Background reading: Loan, Mortgage and Investment Calculators Explained
Nothing is sent anywhere. The figures you type stay in this page and are never transmitted or stored — how that works.
Disclaimer. The formula is exact; the answer is only as good as the figures and assumptions above. Not financial, tax, medical or legal advice. Full disclaimer.