Income-proportional splitting

Fair Share Calculator

Split bills, rent, and expenses fairly — based on income, room size, or custom split ratios. No more arguments about who pays what.

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How It Works

Three steps to a fair split.

1

Enter the total amount

Type in the total bill, rent, or expense you want to split — in any currency.

2

Choose your splitting method

Pick 'By Income' for proportional splits, 'Equal Split' for 50/50, or 'Custom Split' to set exact percentages.

3

Add each person's income

Enter everyone's monthly or annual income. The calculator works out the fair percentage automatically.

Fair Share Calculator
Results update instantly as you type.

Split Details

Who pays what

Total £0.00

What this calculator includes

Income-proportional splitting
Divide any expense so each person pays in proportion to their income. If one person earns twice as much, they pay twice as much — no awkward conversations needed.
Equal splitting
Simple 50/50 (or equal N-way) splits when everyone agrees to go halves regardless of income.
Custom ratio splitting
Set your own percentages for situations like unequal room sizes, different WFH days, or any other arrangement you've agreed.
Up to 6 people
Add up to 6 people to the split — great for group houses, shared offices, and larger households.
One-click copy
Copy the full breakdown to your clipboard and paste it straight into a group chat.

❓ Frequently Asked Questions

How does the fair share calculation work?
The formula is: (your income ÷ combined income) × total bill. So if you earn £3,000 and your flatmate earns £2,000, you pay 60% and they pay 40% of any shared expense.
Should I use monthly or annual income?
Either works — just be consistent. If one person enters monthly income, everyone should enter monthly. The ratio is what matters, not the absolute figure.
What currencies does it support?
Any currency. The calculator uses £ as a display symbol, but the maths works identically for $, €, or any other currency. Just enter the numbers and treat the symbol as a placeholder.
Can I split between more than two people?
Yes — tap "Add Person" to include up to 6 people. The proportional calculation adjusts automatically as you add more.
Is my data saved or shared?
No. Everything runs in your browser — nothing is sent to any server. Refresh the page and the data resets.

From the blog

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Ready to calculate a fair split?

The Fair Share Calculator is free, instant, and takes less than a minute.

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