Split rent fairly between roommates by room size or income.
Please do not make financial decisions based on these results.
What is the Rent Split Calculator?
Split rent fairly between roommates by room size or income. To use the Rent Split Calculator, enter total rent, roommate a room size, roommate b room size, roommate c room size; it returns roommate a pays, roommate b pays, roommate c pays, and shows them instantly as you type.
Where the Rent Split Calculator fits
Split rent fairly between roommates by room size or income. The main figure it returns is the Roommate A pays, worked out from the values you enter.
It belongs with the other budget & planning tools. If you are comparing options or checking a result from another angle, try the Budget Planner (50/30/20), 70/20/10 Rule Money Calculator or the Wedding Budget Calculator.
How to use the Rent Split Calculator
- Fill in the fields. You will need Total rent ($), Roommate A room size (sq ft), Roommate B room size (sq ft), Roommate C room size (sq ft). Start with your real monthly figures, even if they are rounded. Fields marked optional can stay at zero.
- Read the result. The highlighted box gives the Roommate A pays, and the cards below show Roommate B pays, Roommate C pays. Tables and charts break it down further.
- Test other scenarios. Results update as you type. Change one value at a time to see what drives the answer, and press Reset to go back to the defaults.
Formula and how it works
Example with real numbers
Here is the Rent Split Calculator using the default values shown in the calculator above:
Inputs
| Total rent ($) | 3,000 |
|---|---|
| Roommate A room size (sq ft) | 180 |
| Roommate B room size (sq ft) | 120 |
| Roommate C room size (sq ft) | 100 |
Results
| Roommate A pays | $1,350.00 |
|---|---|
| Roommate B pays | $900.00 |
| Roommate C pays | $750.00 |
With these inputs the calculator returns Roommate A pays: $1,350.00. Change any value in the calculator to see how the result moves.
What if you change one input?
Sensitivity check: raising Total rent ($) from 3,000 to 3,600 (about 20% higher) and leaving everything else as in the example above changes the results like this:
| Result | Example | After the change | Change |
|---|---|---|---|
| Roommate A pays | $1,350.00 | $1,620.00 | +20% |
| Roommate B pays | $900.00 | $1,080.00 | +20% |
| Roommate C pays | $750.00 | $900.00 | +20% |
The input that moves the result most is the one to check twice. Change it in the calculator above to test your own case.
What the results tell you
The results panel of the Rent Split Calculator reports Roommate A pays, roommate b pays and roommate c pays. Compare these figures while changing one input at a time, and use the related calculators below to look at the same situation from another angle.
Method and limits. This calculator applies the formula in the section above to your inputs, in your browser; nothing you enter is stored on our servers. Results are only as good as the figures you enter; use real recent numbers. It is for information, not financial, tax or legal advice.
Frequently asked questions
What is the fairest rent split?
Weight by room size and extras like a private bathroom or by income, depending on what you agree on.
How do I start a budget?
List your take-home income, list every regular expense, and compare. Adjust until spending is below income with room for savings.
How accurate are cost-of-living indexes?
They are averages and estimates. Housing costs vary widely within a city, so use the result as a guide and check real rents and prices.
Are the results guaranteed?
No. Results depend entirely on the numbers you enter and the formulas shown on this page. Please do not make financial decisions based on them alone; confirm important figures with a licensed professional.
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