Discount & sales tax calculator
Shops are good at making a discount sound larger than it is, particularly when they stack one offer on another. Enter the original price and the offers and this tells you the price at the till and the true percentage off.
How to use the discount & sales tax calculator
- Enter the original price.
- Add the advertised discount, and a second stacked discount if there is one.
- Add sales tax or VAT if it is charged on top rather than included.
How it works
Stacked discounts multiply rather than add. Taking 30% off and then a further 20% off leaves you paying 0.7 × 0.8 = 0.56 of the original, which is a 44% discount, not 50%. The effective discount line shows the real figure.
Tax is applied to the discounted price, not the original, so a genuine reduction also reduces the tax you pay on the item.
Common questions
Is '50% off, then 20% off' the same as 70% off?
No — it works out to 60% off. Successive discounts apply to the already-reduced price, which is why the effective discount line is worth checking.
How do I find the original price from a sale price?
Divide by one minus the discount. A 25%-off item sold at 90 was originally 90 ÷ 0.75 = 120.