Discount Calculator — the United Kingdom
Calculate UK sale prices, find the percentage off, or reverse the original price. Includes VAT-inclusive totals, stacked markdowns, and bulk quantity pricing.
Quick check — see the price after a percentage discount.
United Kingdom Discount Notes
UK discount pricing is usually shown on VAT-inclusive shelf prices, which means the advertised markdown and the post-discount VAT portion often matter together for shoppers and small businesses.
This version is tuned to UK retail pricing, where VAT-inclusive comparisons, stacked markdowns, and quantity breaks are common.
UK-specific treatment for discount: figures are framed in pounds, with British household or business wording and the assumptions commonly seen in PAYE, HMRC, mortgage, pension, and consumer-credit contexts.
Watch for UK markers in the page copy and inputs: HMRC, PAYE, National Insurance, pension contributions, stamp duty land tax, miles, APR, part-exchange, council tax, VAT, and GBP-based totals.
The result should be read as a United Kingdom estimate, so compare it with UK provider quotes, HMRC or GOV.UK guidance, lender affordability rules, devolved-nation differences, or regulated advice where needed.
Results update instantly. Stacked discounts multiply — not add.
In the United Kingdom, VAT is included in almost all retail prices. Discounts are applied to the VAT-inclusive price.
Discounts in the United Kingdom are applied to the full VAT-inclusive price. A £200 price tag includes £33.33 of VAT (£200 ÷ 6 at the standard 20% rate). After a 25% discount: sale price = £150, which includes £25.00 of VAT. The VAT amount drops with the discount.
To find VAT in a VAT-inclusive price: divide by 6 (at the standard 20% rate). To find the ex-VAT price: multiply by 5/6 (or divide by 1.2). To add VAT to an ex-VAT price: multiply by 1.2. Use Standard mode to see the full breakdown on any discounted price.
Some items carry no VAT in the United Kingdom: most food, children’s clothing, and books and newspapers are zero-rated. If the item you’re discounting is zero-rated or exempt, select “Not applicable” in the VAT field — the sale price calculation remains the same but no VAT breakdown is shown.
Stacked discounts multiply, not add. “30% off then extra 15% off” does not equal 45% off.
Two discounts applied sequentially: (1 − 30%) × (1 − 15%) = 0.70 × 0.85 = 0.595. You pay 59.5% of the original price. Effective discount = 40.5%, not 45%. The second discount is applied to the already-reduced price, not the original.
“Extra 15% off all sale items” sounds generous but the 15% is applied to the already-reduced price. On a £500 item at 30% off (£350), the extra 15% saves £52.50 — not £75. Use Detailed mode to model any combination of stacked discounts.
Mathematically, the order of applying two discounts makes no difference to the final price. 30% then 15% = 15% then 30% = 40.5% effective discount either way. Where order does matter: if a fixed-amount discount is applied (e.g. £20 off after a % discount), apply the % first.
UK consumer law — principally the Digital Markets, Competition and Consumers Act 2024, enforced by the CMA and Trading Standards — sets rules on how retailers advertise discounts.
The “was” price in a “was £X, now £Y” tag must have been a genuine price at which the item was sold for a reasonable period. Retailers cannot inflate a “was” price to make a discount appear larger. If you suspect a fake “was” price, report it to your local Trading Standards service via the Citizens Advice consumer helpline.
If a retailer says “up to 70% off”, only one item needs to be 70% off — most items can be a much smaller discount. The rules require that the most prominent discount claim is not misleading. “Up to X% off” claims are often used strategically to attract customers.
A displayed price is an “invitation to treat”, so a retailer is not legally obliged to sell at a mispriced shelf price — but most will honour a genuine error at the till. If you were charged more than the advertised discounted price, you can ask for a refund of the difference under the Consumer Rights Act 2015. Keep receipts for price comparison.
Three discount formulas — sale price, discount %, and original price
| Calculation | Formula & example |
|---|---|
| Sale price | Original × (1 − Discount%) → £200 × 0.75 = £150 (25% off) |
| Discount % | (Original − Sale) / Original × 100 → (£350 − £280) / £350 × 100 = 20% |
| Original price | Sale / (1 − Discount%) → £180 / 0.75 = £240 (was 25% off) |
Quick mental discount calculations for common percentages
| Discount | Mental shortcut |
|---|---|
| 10% off | Move decimal left one place → £250 × 10% = £25 saving → £225 |
| 20% off | Divide by 5, subtract → £300 ÷ 5 = £60 saving → £240 |
| 25% off | Divide by 4, subtract → £200 ÷ 4 = £50 saving → £150 |
| 50% off | Simply halve the price → £180 ÷ 2 = £90 |
| 30% off | 10% × 3, subtract → £200 × 10% = £20 × 3 = £60 off → £140 |
| 15% off | 10% + half of 10% → £200: 10% = £20, half = £10; total = £30 off → £170 |
How VAT interacts with discounts on UK retail prices
Discounts are on VAT-inclusive prices
Almost all retail price tags in the United Kingdom include VAT. Discounts are applied to the full VAT-inclusive price. The discounted sale price also includes VAT, just a proportionally smaller amount.
| Price point | VAT breakdown |
|---|---|
| £200.00 original (incl. VAT) | VAT = £33.33 · Ex-VAT = £166.67 |
| £150.00 sale (25% off) | VAT = £25.00 · Ex-VAT = £125.00 |
| £100.00 sale (50% off) | VAT = £16.67 · Ex-VAT = £83.33 |
To estimate the VAT portion from a VAT-inclusive price, divide by 6 when using the standard 20% rate. Add VAT to an ex-VAT price using the applicable rate for the product.
How stacked discounts work — and why 30% + 15% ≠ 45%
When two discounts are applied sequentially, they multiply — not add. The second discount applies to the already-reduced price, not the original. This means the combined effective discount is always less than the sum of the two rates.
| Discount combination | Effective combined rate |
|---|---|
| 20% + 10% | 28% effective → (1-0.20) × (1-0.10) = 0.72 → 28% off |
| 30% + 15% | 40.5% effective → (1-0.30) × (1-0.15) = 0.595 → 40.5% off |
| 50% + 20% | 60% effective → (1-0.50) × (1-0.20) = 0.40 → 60% off |
Frequently askedFrequently asked questions
How do I calculate a discount percentage?
Discount % = (Original price − Sale price) / Original price × 100. Example: original £200, sale £150. Discount = £50 / £200 × 100 = 25%. Use the “Find discount %” mode in this calculator to do this automatically.
Do stacked discounts add up?
No. Stacked discounts multiply, not add. “30% off then extra 15% off” does not equal 45% off. The effective combined discount is (1 − 0.30) × (1 − 0.15) − 1 = 40.5%. The second discount is applied to the already-reduced price.
Does VAT apply to discounted prices in the United Kingdom?
Yes. In the United Kingdom, discounts are applied to the VAT-inclusive price. The discounted sale price still includes VAT at the standard 20% rate. To find the VAT in any VAT-inclusive price, divide by 6. Use Standard mode in this calculator to see the full VAT breakdown.
Can I find the original price if I only know the sale price?
Yes. Original price = Sale price / (1 − Discount%). Example: paid £180 after 25% off. Original = £180 / 0.75 = £240. Use the “Find original price” mode in this calculator.
What are the rules on discount advertising in the United Kingdom?
The “was” price in a “was £X, now £Y” advertisement must be a genuine previous price at which the item was sold for a reasonable period. Under the Digital Markets, Competition and Consumers Act 2024, retailers cannot inflate a reference price to create the appearance of a larger discount. Report misleading discount advertising to your local Trading Standards service (via the Citizens Advice consumer helpline) or the Competition and Markets Authority (CMA).