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 | Statewide 0–7.25% (+ local) | 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 is added at the register (statewide statutory rates 0–7.25%; city and district tax is extra), 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.