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Bill Split Calculator

Split monthly bills evenly, rotate who pays each vendor so one person is not floating everything, and see who owes whom. For the rent fight, use the rent-split calculator.

How should roommates split bills?

Add every shared monthly bill, divide by headcount for each person's fair share, then assign each vendor to one roommate this month. Anyone who paid more than their fair share gets paid back by anyone who paid less. Rotate the payer list next month so the float moves around.

1. Roommates

Add 2 to 6 people who share the bills.

2. Monthly bills

Defaults cover the usual three. Add trash, gas, streaming, or anything else you split.

Each month, bump this forward one step so a different person pays each vendor over time.

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This month's plan

Add roommates and bills, then hit calculate.

Also splitting rent?

Open the rent-split calculator

Different rooms can justify different rent shares. Use that tool for the rent, and keep this one for utilities and shared bills.

Rent Split Calculator

Next step

Put payment rules in writing

Agree who pays which vendors, when the float is settled, and what happens if someone is late. A short written note beats a group chat from three months ago.

Create an agreement

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How this calculator works

Every bill is divided evenly by the number of roommates. That is each person's fair share of that bill. Then the tool assigns each bill to one roommate for this month so the vendors still get paid by a real person.

  • Fair share: total of all bills divided by headcount.
  • Who pays the vendor: bills are handed out in order, rotating through the roommate list. Change the rotation start each month.
  • The float: if you paid vendors more than your fair share, others owe you. If you paid less, you owe the people who covered you.

This is not a running ledger, Splitwise replacement, or auto-pay tool. It is a clear monthly plan you can copy into a group chat or print.

Examples

Example 1. Alex, Jordan, and Sam share Internet $75, Electric $120, and Water $45. Total $240. Fair share is $80 each. This month Alex pays Internet ($75), Jordan pays Electric ($120), and Sam pays Water ($45). Against the $80 fair share, Alex still owes $5, Sam owes $35, and Jordan is owed $40. Settle-up: Sam pays Jordan $35 and Alex pays Jordan $5.

Example 2. Four roommates and five bills. Some people will pay two vendors in a given month. That is fine. Their fair share stays total divided by four. The extra vendor payment shows up as a larger float that others settle.

How to talk about it

  • Agree on the list first. Decide which bills are shared before arguing about who pays which one.
  • Separate rent from utilities. Rent can follow room value. Bills usually follow headcount. Mixing the two creates confusion.
  • Pick a settle-up day. The first Saturday after bills post, or the day rent is due, works better than "whenever."
  • Rotate on a calendar. Screenshot the three-month preview and drop it in the house chat so the pattern is obvious.
  • Write the rule once. Who pays which vendors, how the float is settled, and what happens if someone is late.

Common questions

How should roommates split utility bills?

Equal shares by headcount is the least contentious default. Add the monthly bills, divide by the number of people, and settle so everyone ends at that fair share even if only a few people pay the vendors.

Why rotate who pays which bill?

If the same person always pays internet, electric, and water, they float the household's cash until everyone pays them back. Rotating which roommate pays which vendor spreads that float and keeps one person from chasing everyone else every month.

What is the float between roommates?

The float is the gap between what someone paid the vendors this month and their fair share. If Alex paid $180 in bills but owes only $120 as a fair share, the others owe Alex $60 in total.

Should rent and utilities be split the same way?

Often no. Rent may follow room size and amenities. Utility bills usually follow headcount, because everyone uses the kitchen, water, and internet. Use this tool for bills and the rent-split calculator for the rent itself.

Does this track unpaid balances over time?

No. It plans one month at a time. If you need a running balance, keep a shared note or spreadsheet. This tool stays simple on purpose.

Is any of this legally binding?

No. This is a math tool, not a legal document. What makes a payment arrangement reliable is a written note everyone accepts, and in some situations a room rental agreement that follows your state's rules.

Educational information only. RoomRental.com does not provide legal, tax or financial advice. Rules for deposits, utilities, and shared housing vary by state and city. Confirm anything that matters with a qualified professional in your area.