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.
Calculate the tip, the grand total and each person's fair share from any bill amount and tip percentage — ideal for splitting a restaurant cheque. Everything is worked out in your browser.
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
- Splitting a restaurant bill between friends without doing mental arithmetic
- Working out a fair tip percentage when travelling somewhere with different norms
- Checking whether a service charge has already been added before tipping again