Discount Calculator Online - Sale Price & Savings

Frequently asked questions

How do I work out a discount by hand?

Multiply the original price by the discount percentage to get the saving, then subtract it: £80 at 25% off is £80 × 0.25 = £20 saved, so £60 to pay. The shortcut is to multiply by what you still pay — £80 × 0.75 — which gets there in one step.

How do stacked discounts work — is 20% then 10% the same as 30%?

No, and the difference catches people out. Successive discounts apply to the already-reduced price, so 20% then 10% off £100 gives £72, not £70. Stacked percentages always total less than their sum.

Does the calculation include sales tax or VAT?

The discount is applied to whatever figure you enter. If your price already includes VAT, the result includes it too; if it excludes VAT, add the tax to the discounted figure afterwards.

Pro tips

Divide, never subtract, when working backwards from a total to find the amount before tax or before a discount.
Compare loans on total interest paid rather than the monthly payment — a longer term lowers the monthly figure while costing considerably more overall.
Watch for stacked discounts: 20% off then a further 10% off is 28% off, not 30%, because the second applies to the reduced price.
State whether you mean percentage points or percent when reporting a change; the two differ by a factor that can be enormous.
For a tip split, agree whether the tip is calculated before or after tax before dividing — the two give different answers and both are conventional somewhere.

About Percentage & Finance Calculator

The loan figures use the standard amortising formula, where the monthly payment stays level while the split between interest and principal shifts across the term. That is why total interest, rather than the monthly number, is the figure worth comparing between two offers.

Work out the final sale price and exactly how much you save from any percentage discount in seconds. The figures are calculated on your device, alongside tip and loan tools.

Work out percentages and percentage change, sale discounts and final prices, tip splits per person, and monthly loan or EMI payments with total interest — all in one place. It covers the everyday money maths that comes up while shopping, dining out, budgeting and comparing loans.

Switch between modes to answer 'what is X% of Y', 'how much do I save', 'what is each person's share' or 'what will this loan cost'. Percentage change is the one to double-check: 40 rising to 50 is a 25% increase, while 50 falling back to 40 is a 20% decrease.

Two percentage mistakes are common enough to be worth naming. The first is confusing a percentage change with a percentage point change: a rate moving from 2% to 3% is a rise of one percentage point and an increase of fifty percent, and both statements are true of the same movement. The second is assuming changes cancel — an item discounted 20% then raised 20% does not return to its original price, because the increase is calculated on the smaller figure. £100 becomes £80 and then £96.

Reversing a percentage is the operation people most often get backwards. To find the pre-tax figure inside a £120 total at 20% tax, you divide by 1.2 to get £100; subtracting 20% of £120 gives £96 and is simply wrong. The same applies to working out an original price from a sale price. Whenever you are undoing a percentage rather than applying one, the operation is division.

Common use cases

Checking a sale price at the shelf before deciding whether it is really a deal
Working out the final price when a voucher stacks on top of a sale
Setting a promotional price that still clears a target margin

How it comparesA spreadsheet handles all of this and requires you to write the formula correctly, which is where the reversal errors happen. Dedicated loan calculators from lenders tend to foreground the monthly payment; seeing total interest alongside it is what makes two offers comparable.