Discount Calculator
Find the sale price after a percentage off, work out what percent off you got, reverse-calculate the original price, or combine stacked discounts. Add VAT or sales tax to see what you actually pay at the till.
Sale price = Original × (1 − %÷100) · % off = (1 − Sale ÷ Original) × 100 · Original = Sale ÷ (1 − %÷100) · Stacked = Original × (1 − D₁÷100) × (1 − D₂÷100). Stacked discounts multiply, they never add — 20% + 10% = 28% off, not 30%.
Price is $80, 25% off — what do I pay?
How to Calculate a Discount
1. Sale Price — How Much Will I Pay?
Formula: Sale price = Original × (1 − Discount% ÷ 100)
Example: a $80 jacket at 25% off = 80 × 0.75 = $60. You save 80 × 0.25 = $20. Quick mental shortcuts: 10% off = move the decimal one place; 25% off = subtract a quarter; 50% off = halve it.
2. Percent Off — What's the Deal Really Worth?
Formula: Percent off = (1 − Sale ÷ Original) × 100
Example: an item marked down from $80 to $60 = (1 − 60÷80) × 100 = 25% off. This is the number to compare across stores — a bigger sticker price with a bigger discount is not always cheaper.
3. Original Price — Was the "Was" Price Real?
Formula: Original = Sale ÷ (1 − Discount% ÷ 100)
Example: you paid $60 after a 25% discount → 60 ÷ 0.75 = $80. Reverse-calculating the original is the easiest way to sanity-check inflated "reference" prices used in some sales.
4. Stacked Discounts — Why 20% + 10% ≠ 30%
Formula: Final = Original × (1 − D₁÷100) × (1 − D₂÷100)
Example: a $100 item at 20% off, then an extra 10% off = 100 × 0.80 × 0.90 = $72, an effective 28% off — not 30%. Each discount is taken from a smaller base, so percentages multiply instead of adding. The final total is the same regardless of which discount is applied first.
Discounts & Tax Around the World
The discount maths is universal, but whether the price you start from already includes tax is not. This changes what "25% off" actually means at the register.
| Country / Region | Tax on Goods | Shelf Price Includes Tax? | What "25% off" Means |
|---|---|---|---|
| 🇺🇸 United States | Sales tax 0–10.25% | No — added at checkout | Discount off pre-tax price; tax added after |
| 🇬🇧 United Kingdom | VAT 20% | Yes — VAT included | Discount off the VAT-inclusive shelf price |
| 🇪🇺 European Union | VAT 17–27% | Yes — VAT included | Discount off the VAT-inclusive price |
| 🇨🇦 Canada | GST/HST 5–15% | No — added at checkout | Discount off pre-tax price; tax added after |
| 🇦🇺 Australia | GST 10% | Yes — GST included | Discount off the GST-inclusive price |
| 🇯🇵 Japan | Consumption tax 10% | Usually shown both ways | Check 税込 (incl.) vs 税抜 (excl.) label |
Frequently Asked Questions
How do I calculate the sale price after a percentage off?
Multiply the original price by (1 − discount÷100). For 25% off $80: 80 × (1 − 0.25) = 80 × 0.75 = $60. The amount you save is 80 × 0.25 = $20. A quick shortcut for 25% off: divide the price by 4 to get the saving, then subtract.
How do I work out what percent off I got?
Percent off = (1 − sale price ÷ original price) × 100. If an item was $80 and is now $60: (1 − 60÷80) × 100 = 25% off. The amount saved is $80 − $60 = $20.
Is 20% off then an extra 10% off the same as 30% off?
No. Stacked discounts multiply rather than add. 20% off followed by an extra 10% off is 0.80 × 0.90 = 0.72, which is 28% off the original — not 30%. On a $100 item you pay $72, not $70. Which discount is applied first only matters for rounding; the final price is identical either way.
Does the discount apply before or after sales tax?
It depends on the country. In the United States, sales tax (0–10.25% depending on state) is added at the register, so a discount is applied to the pre-tax price and tax is charged on the lower amount. In the UK and EU, the shelf price already includes VAT (UK 20%, EU 17–27%), so a 25% off sticker reduces the tax-inclusive price directly.
How do I find the original price from a sale price?
Divide the sale price by (1 − discount÷100). If you paid $60 after a 25% discount: 60 ÷ (1 − 0.25) = 60 ÷ 0.75 = $80 original price. This is useful for checking whether an advertised original price is genuine.
What is the difference between a discount and a markup?
A discount reduces a price by a percentage of itself: $100 − 20% = $80. A markup increases a cost by a percentage: $100 + 20% = $120. They are not reversible — a 20% markup followed by a 20% discount does not return the original ($120 × 0.80 = $96), because each percentage is taken from a different base.
How do I calculate 30% off a price quickly?
Find 10% by moving the decimal one place left, multiply by 3 to get 30%, then subtract from the price. Example: 30% off $50 → 10% = $5, 30% = $15, sale price = $35.
What does up to 70% off actually mean?
Up to means 70% is the maximum discount on a few items — most products will be discounted far less. Always check the individual ticket price rather than the banner.
Sources & Methodology
Discount, percent-off, reverse-price and stacked-discount results are computed client-side from the standard formulas shown above. Country tax treatment reflects whether the displayed retail price is tax-inclusive (VAT/GST) or tax-exclusive (US/Canada sales tax).
- GOV.UK — VAT rates on different goods and services
- European Commission — VAT rates applied in EU member states
- Australian Taxation Office — GST
- Canada Revenue Agency — GST/HST rates
Standards and figures reviewed June 2026.