Shared Household Calculators
Utility bill splitter.
Enter the bill, any fixed charges, and each person's days at home or usage. Pick equal, days or usage and see what each person pays, with the shares adding up to the bill exactly. Runs in your browser; nothing is sent or stored.
Bill and people
Result
Fill the form and press Calculate.
Worked example
A 180.00 bill includes 30.00 of fixed charges, 10.00 each for three people. The other 150.00 is split by usage: Alex used 420, Sam 300 and Jo 180, 900 in total, so their variable shares are 70.00, 50.00 and 30.00. Alex pays 80.00, Sam 60.00 and Jo 40.00. On equal shares each would pay 60.00.
How it works
Fixed charges are split equally; the rest by weight. The weight is 1 for equal shares, the days a person was home, or their usage. Each person's variable share = (bill - fixed) x their weight / total weight. Money is rounded to the cent with the largest-remainder method, so the shares add back to the bill exactly. Use days when people were away, and usage only if you have real readings such as sub-meters. A common rule of thumb, not a published standard: if you cannot measure use, days at home is the fairest default.
Sources and basis (checked 2026-10-08): arithmetic on the numbers you enter, with no external constants or published figures. Amounts are in whatever currency you enter. This is a calculation aid, not legal, tax or financial advice.
FAQ
How do I split a utility bill fairly with roommates?
Split it by whatever drives the cost. Use equal shares if everyone lives there all month and uses about the same, days at home if people come and go, and usage if you have sub-meters or readings. This tool does all three.
Why are fixed charges split equally?
A connection or service fee does not change with how much anyone uses, so it is split evenly and the chosen method is applied to the rest. Enter 0 in the fixed charges box to apply one method to the whole bill.
What if someone was away for part of the month?
Choose days at home and enter the days each person was in the home. Use the move-in and move-out bill splitter if the dates matter day by day.
How are odd cents handled?
Each share is rounded down to the cent and the leftover cents go to the largest remainders, so the shares always add up to the bill.
Can I use it for water, gas or internet?
Yes. It works for any shared bill. Enter usage in whatever unit your meter reports, as long as it is the same unit for everyone.