Everyday Calculators
Seventeen simple tools for the numbers that come up every day — tips, percentages, loans, VAT, savings, debt, margin, fuel cost, BMI and more. Pick one to get started.
Tip
Percentage
Discount
Discount Calculator — see the sale price and your savings
A discount calculator shows the final price after a percentage off, and how much money you save. It is perfect for sales, Black Friday deals, clearance racks and coupon codes.
How to calculate a discount
Multiply the original price by the discount percentage to get your saving, then subtract it from the original price. Enter the price, pick a discount (10%, 20%, 30% or 50%) or type your own, and both numbers appear instantly.
Example
A $120 jacket at 30% off saves you $36, so you pay $84.
Stacking two discounts
Two discounts do not simply add up. 20% off and then another 10% off is not 30% off: the second cut applies to the already-reduced price. 20% off €100 is €80, then 10% off is €72 — an effective discount of 28%. Here is what common pairs really come to:
| First + second | Actual total off |
|---|---|
| 20% + 10% | 28% |
| 25% + 25% | 43.75% |
| 30% + 20% | 44% |
| 50% + 10% | 55% |
| 50% + 20% | 60% |
Formula: total off = 1 − (1 − first) × (1 − second). Stacked discounts are always less than the two added together.
Is the discount applied before or after tax?
Shops usually take the discount off the pre-tax price and then add tax to the reduced amount. Enter the pre-tax price here to see the discounted figure, then use the VAT calculator if you need the final price at the till.
Spotting a real bargain
Compare the final price you pay, not the size of the percentage. A ‘50% off’ inflated price can still cost more than a ‘20% off’ fair price. Checking the price per unit is the honest test.
How the discount is worked out
The sale price is the original price multiplied by one minus the discount — a 30% discount means you pay 70%, so a 50 item costs 50 × 0.70 = 35. Your saving is the difference, 15. Two discounts do not simply add: 20% then 10% off is 0.8 × 0.9 = 0.72, a 28% reduction, not 30%.
As a quick mental check, a 50% discount always halves the price, and taking 10% off is the same as removing one tenth.
VAT
Bill Split
Unit Converter
Loan & Mortgage
Mortgage
Salary Converter
Compound Interest
BMI & Calories
Date & Age
Time & Hours
Debt Payoff
Area
Margin & Markup
Fuel Cost
FAQ
How do I calculate the sale price after a discount?
Multiply the original price by (100 − discount%) ÷ 100. £50 with 20% off is £40.
How much do I save?
Multiply the original price by the discount percentage. 20% off £50 saves £10.
How do I combine two discounts?
Apply them one after the other, not by adding. 20% then 10% off £100 is £72, not £70.