What this calculator does
When a roommate moves out, three things are usually left to settle at once: the last rent and utility bills, the deposit, and the furniture you bought together. This calculator works out each one with its own rule, adds them up per person, and turns the result into a short list of transfers, so nobody sends money three times. Every number shows the working.
You enter the people with the day each moved in or out (leave it empty for the whole period) and, for rent by room, each room's monthly rent; each final bill with its amount, the period it covers and who paid it; what each person put into the deposit, the deductions and who gets the refund; and each shared item with its price, when it was bought, how many years it lasts, who owns it and who keeps it.
The three rules
- Final bills, by days lived. Each bill covers a period. Each roommate's part follows the days they lived there in it, counting the first and last day. Rent can be split by room rent and days instead, so a bigger room pays more.
- The deposit, by where each deduction is. Shared space is split evenly between everyone who put money in. A deduction for one room belongs to whoever has that room.
- Shared stuff, at its value now. The price, less an even share for each month used over the years it lasts. Whoever keeps it pays the other owners their share of that value.
These are the calculator's own rules, written out with their formulas on the methodology page. A bill's daily rate, for example, is calculated as the amount divided by the days it covers, counting both ends.
An example
Rent for a room that stands empty
Say September's rent of $2,400.00 is split by room rent: Ana $900.00, Ben $800.00 and Cal $700.00 a month. By room rent and days lived, Cal's part is $339.39, not $280.00 (12 thirtieths of $700.00): the 18 days Cal's room stood empty still had to be paid, and they fall to Ana and Ben. If Cal agreed to pay until the end of a notice period, enter that day as Cal's move-out day.
30 days or the days in the month
The calculator counts the real days in each bill's period, both ends included, so August has 31 days and February 28 or 29. Some leases use a 30-day month instead. The difference is small but it is money, so match the lease.
This works for months with 31 days. In February the period cannot be stretched to 30 days; the lease's figure there is the rent divided by 30, times the days lived. Which count applies is set by the lease, not by this page: look for how it prorates a partial month before you enter the bill.
When the last bill or the deposit comes later
- A late utility bill. Enter an estimate, such as the same month last year, and mark it. When the real bill arrives, open the same page on the same device and type the real amount. The transfers already sent stay as they are, and a top-up list settles only the difference.
- A deposit not refunded yet. The deposit part needs the deductions, which the landlord sends with the refund, and that can come well after the keys are returned. Settle the bills and the shared stuff now, leave the deposit out, and when the refund comes, enter a move-out with only the deposit in it. It gives its own short list. How long a landlord has to return a deposit, and what may be deducted, depend on the lease and on where you live; this page does not say what those rules are, so check the lease and your local rules first.
- The lease goes on. Nothing waits for the landlord: whoever takes over the room pays the one leaving their part of the deposit now.
Common questions
How do you calculate prorated rent?
Divide the rent by the days in its period, then multiply by the days lived, counting the first and last day. Rent of $1,500.00 for September 1 to 30 is $50.00 a day; moving in on September 20 means 11 days, so $550.00. Each bill on this page shows its daily rate, and the prorated amount when one person lived there.
How do you split utilities when a roommate moves out mid-month?
By the days each person lived there during the bill's period, counting the first and last day. A $90.00 electricity bill for September 1 to 30, with one roommate leaving on September 12, splits 30 : 30 : 12, which is $37.50, $37.50 and $15.00.
Is prorated rent based on 30 days or the days in the month?
The calculator counts the real days in the bill's period. Rent of $2,100.00 for August 1 to 31, for someone who lived there 10 days, is $677.42; on a 30-day month it would be $700.00. If your lease says 30 days, end the bill's period on August 30 and the daily rate becomes $70.00.
Who pays the rent for an empty room after someone moves out early?
Split by room rent and days lived, the days nobody was in that room fall to the roommates still there, in proportion to their rent. If the one leaving agreed to pay until the end of their notice period, enter that day as their move-out day instead.
How do you split a security deposit between roommates?
Each person gets back what they put in, less their part of the deductions. A deduction for a shared space is split evenly between everyone who put money in; a deduction for one person's room is theirs alone. Whoever receives the refund then sends each person their part.
How much should a roommate pay for shared furniture they keep?
The other owners' shares of what it is worth now. The calculator starts from the price, less an even share for each month used over the years it lasts: a $900.00 sofa used for 24 of its 60 months is worth $540.00, so the one keeping it pays each of the two others $180.00. If the group agrees on another value, type that instead.
What if the last bill or the deposit has not come yet?
Enter the bill as an estimate and mark it; when the real bill arrives, type the real amount on the same device and a short top-up list settles only the difference. A deposit the landlord has not refunded yet can be left out and settled later as a move-out with only the deposit in it.
What it does not do
- It settles up once, when someone moves out. It does not track rent and bills month after month.
- It works in one currency and does not convert. For a trip paid in several currencies, use the trip settle-up.
- It does not tell you what a deposit deduction should be or what your lease or local law says about it. It shows the working for the numbers you enter.
Every result is a reference estimate for the group to agree on; the disclaimer says what that covers. The methodology page lists the rules in full, including who carries a leftover cent. Which way of sharing is fair, for an empty room or a deposit when the lease goes on, is the subject of the guide on prorated rent when a roommate moves out.