Prorated rent calculator
Rent for a partial first or last month, by the method your lease uses. Add free days for a move-in concession and the calculator takes them off the first month.
Same $1,800 rent, three methods
| Move-in | Days occupied | Actual days | 30-day month | Banker’s month |
|---|---|---|---|---|
| 1 Feb (28 days) | 28 | $1,800.00 | $1,800.00 | $1,656.99 |
| 15 Mar (31 days) | 17 | $987.10 | $1,020.00 | $1,006.03 |
| 10 Nov (30 days) | 21 | $1,260.00 | $1,260.00 | $1,242.74 |
| 25 Dec (31 days) | 7 | $406.45 | $420.00 | $414.25 |
The 30-day method charges a full month when the whole month is occupied, whatever its length.
Which method to use
Actual days in the month is the default when the lease is silent and the method most courts would consider fair: the tenant pays exactly for the days of the month they had the unit. Thirty-day month treats every month as 30 days, which makes February slightly more expensive per day and 31-day months slightly cheaper; many older lease forms use it. Banker’s month divides the annual rent by 365 to get a true daily rate (monthly rent × 12 ÷ 365), so the daily rate never changes from month to month; large property managers like it for consistency.
None of these is required by any state statute. Oregon’s and California’s landlord-tenant codes are silent on method, as are the rest. Some online sources claim certain states "require" a formula; we found no statute that does. What the law does require is consistency with the lease: if the lease names a method, that one applies.
Concessions
"Two weeks free" and "first month free" are the common move-in incentives. They are deductions from the first month’s rent, not from the deposit, and most leases spread the clawback risk by making the concession repayable if the tenant breaks the lease early. Enter the free days above to see the cash due at move-in; read the concession addendum for what happens if you leave early.
Frequently asked questions
How do you calculate prorated rent?
Divide the monthly rent by the number of days in that month to get a daily rate, then multiply by the days the tenant occupies the unit. For $1,800 rent and a move-in on the 10th of a 30-day month: $1,800 ÷ 30 = $60 a day × 21 days = $1,260.
Is prorated rent based on 30 days or the actual days in the month?
Either, depending on the lease. No state mandates a method. Actual days is the most common and the fairest; a flat 30-day month is simpler and slightly favours the tenant in 31-day months; the banker’s month (365 ÷ 12 = 30.42 days) is used by some property managers for consistency.
Does a landlord have to prorate rent?
Not by statute in any state, unless the lease says so. In practice almost every landlord prorates a mid-month move-in because the alternative is charging for days the tenant did not have the unit, which is hard to defend if challenged.
How do I prorate rent with a concession like "two weeks free"?
Convert the concession to days (14 for two weeks) and subtract 14 days at the daily rate from the first month’s prorated amount. If the concession is bigger than the first month, the balance usually carries to the second month; the calculator shows the first month only.
Is the move-out month prorated?
Only if the lease or notice allows a mid-month end. Most month-to-month tenancies end on the last day of a rental period, so there is nothing to prorate. Where a mid-month move-out is agreed, the same daily rate applies to the days occupied.