How to Calculate Prorated Rent Accurately

To prorate rent, multiply a daily rate by the number of days you have the unit in a partial month. The daily rate comes from one of three methods: the month's rent divided by the days in that month, a year's rent divided by 365, or the month's rent divided by 30. On $1,800 rent for 12 days of a 31-day month, those methods give $696.77, $710.14, and $720.00. Check which method your lease names, and check your state's notice rules, which decide whether you can end a tenancy partway through a month at all.

The three ways to set a daily rate

Multiply the daily rate by the number of days you have the unit, counting both the first and the last day, and round the result to the cent. Use the unrounded daily rate in the multiplication so rounding does not shift the total by a few cents.

The methods give different answers depending on the month. In a 31-day month, the 30-day method charges the most. In February, the actual-days method charges the most. In a 30-day month, the actual-days and 30-day methods match, and the 365-day method is a little lower.

Move-in example

Your lease starts August 20, rent is $1,800 due on the 1st, and you have the unit August 20 through 31, which is 12 days (31 minus 20, plus 1).

A February start shows the opposite pattern. For a lease starting February 15, 2027, you have the unit for 14 days, February 15 through 28. The actual-days method gives $1,800 / 28 x 14 = $900.00, the 365-day method gives $828.49, and the 30-day method gives $840.00. Here the actual-days method costs $71.51 more than the 365-day method.

Check when the partial-month rent is due. If your lease collects it at signing along with the first full month, the amount due on these numbers is $696.77 plus $1,800 for September, or $2,496.77, before any deposit. Move-in fees vs. security deposits covers the other charges due at signing.

Move-out example

You end a month-to-month tenancy on October 10, in a state that allows a mid-month end date. You owe rent for October 1 through 10, which is 10 days of a 31-day month:

If you already paid the full $1,800 for October under the actual-days method, ask the landlord in writing to refund or credit the unused $1,219.35.

When state law or the lease decides

Start with your lease: if it names a method, check the landlord's figure against that method. If it is silent, some state laws set a default: Arizona's landlord-tenant act, for example, says rent is apportionable day to day unless you and the landlord agree otherwise. That makes daily proration the rule there, but it does not pick a divisor, so ask the landlord which method it uses.

Whether you can owe rent for only part of your last month depends on your state's rules for ending a tenancy:

• California: you can end a month-to-month tenancy with at least 30 days' written notice given on any day, and rent is due through the termination date (Civil Code section 1946).
• Oregon: a month-to-month tenant can give at least 30 days' written notice ending on any date, and owes rent until the notice expires, or until a new tenant's tenancy begins if that is sooner (ORS 90.427 and 90.220).
• Texas: unless you and the landlord signed an agreement setting a different notice period, a month-to-month tenancy ends on the later of the date in your notice or one month after you give it. If that date falls mid-month, you owe rent only up to the termination date (Property Code section 91.001).
• Florida: you must give at least 30 days' written notice before the end of a monthly rental period, so a month-to-month tenancy ends on the last day of a rental month and there is no partial final month unless the landlord agrees.
• Washington: you must give at least 20 days' written notice before the end of a rental period, so the tenancy also ends on the last day of a period (RCW 59.18.200).

If you are a service member ending a lease under the federal Servicemembers Civil Relief Act, rent for the period before the termination takes effect is owed on a prorated basis, and rent you paid in advance for time after it must be refunded within 30 days. A fixed-term lease that ends mid-month follows the lease's end date and method; what happens when your lease expires covers staying on afterward, and notice to vacate requirements covers how much notice to give.

How to check your landlord's math

1. Find the monthly rent, the start or end date, and the proration method in your lease.
2. Count the days you have the unit, including the first and last day.
3. Compute the daily rate with the lease's method, multiply by the days, and round to the cent.
4. Compare your figure with the charge. If it is higher, ask the landlord in writing for its calculation; how to dispute incorrect rent charges covers the next steps.
5. Get a receipt that shows the prorated amount and the dates it covers. Rent payment rules for tenants covers receipts, due dates, and late fees.