How to split electricity, water and gas bills with roommates
Rent is fixed; utilities change every month. With a single meter there is no way to see who used how much, so bills trigger more "is this fair?" arguments between roommates than rent does.
Here are four common ways to split electricity, water and gas, a day-based calculation for someone who moved in mid-month, and practical tips.
1. Equal split
The bill total is divided by the number of people. $240 bill, 3 people: $80 each. It causes the least arguments when everyone is home about as much and uses about the same.
Best when: usage differences are small, everyone lives there full time and there is a single meter.
2. Day-based split
If someone moved in mid-month or was away for a long time, splitting by person-days is fair. Example: a $240 bill for a 30-day month.
| Person | Days at home | Share | Pays |
|---|---|---|---|
| Alex | 30 | 30/75 | $96 |
| Sam | 30 | 30/75 | $96 |
| Jordan (moved in mid-month) | 15 | 15/75 | $48 |
| Total | 75 person-days | $240 |
Math: $240 ÷ 75 person-days = $3.20 per person-day; each person pays for the days they were there.
3. Split by usage
If one person works from home or runs an air conditioner or space heater, an equal split may be unfair. Options:
- Agree a fixed difference: for example the person working from home pays 40% of the electricity, the others 30% each.
- Extra share for a device: whoever runs their own heater covers its estimated use.
- Sub-meters: separate meters per room are the most accurate method; you need to talk to the landlord.
The key is an agreed ratio, set in advance and openly. Differences that surface later cause resentment.
4. Fixed monthly amount
Everyone pays a fixed amount each month (say $80 each) and bills are paid from the pot. At year end any surplus or shortfall is evened out. It smooths out the winter-summer swing, but whoever manages the pot has to keep clear records.
Example: a high winter gas bill
Three roommates, January bills (example): electricity $90, water $30, gas $270, internet $45. Total $435.
| Method | Per person | Note |
|---|---|---|
| Equal split every month | $145 | High in winter, low in summer: big swings |
| Fixed yearly average | Say $90 | Difference evened out at year end |
With a fixed amount the person who overpays in winter underpays in summer, so there are no monthly surprises. At year end compare total bills with total payments and settle the difference.
Moving out and account names
Utility accounts are usually in one person's name. If that person moves out, the accounts need to be transferred or closed. Without a transfer, the person who left can remain responsible for later bills, so discuss account ownership when someone is leaving (see our moving-out guide).
6 ways to bring the bills down
- Turn off heating and lights in empty rooms.
- Run the washing machine and dishwasher full.
- Agree on shower length and hot-water settings.
- Set the thermostat as a household; separate settings push the bill up.
- Switch devices off instead of leaving them on standby.
- Log every bill each month; sudden jumps point to leaks or faults early.
Frequently asked questions
How do roommates split utility bills?
Most split equally. If someone moved in mid-month or usage differs a lot, a day-based split or a ratio agreed in advance is fairer.
How should roommates split a gas heating bill?
If the boiler is shared, split it equally. Because it spikes in winter, a fixed monthly average settled at year end avoids unpleasant surprises.
Should a roommate who is away still pay the bill?
For short absences the split usually stays equal. For long absences (a month or more), use a day-based calculation or a discount agreed beforehand.