This prorated rent calculator figures out exactly what you owe when you move in partway through a month: the daily rate, the number of days you occupy the unit, and the partial month rent that results. Enter your monthly rent, pick your move-in date, and choose how your landlord prorates.
Both common methods are supported. The actual-days method divides rent by the real number of days in your move-in month (28–31), while the 30-day banker’s month method divides by a flat 30 regardless of the calendar. The difference is small but real — and your lease decides which one applies.
How to Prorate Rent (the Formula)
Prorated rent is a simple two-step calculation:
1. Daily rate = Monthly rent ÷ days in the month (or ÷ 30 under the banker’s method) 2. Prorated rent = Daily rate × days you occupy, counting the move-in day itself
Days occupied = (days in month − move-in day + 1). Move in on the 20th of a 30-day month and you occupy 11 days: the 20th through the 30th.
Some landlords instead prorate by the year — (rent × 12 ÷ 365) per day — which produces a slightly different daily rate. There is no single federal rule; the method in your lease (or, in a few states, statute) controls, so this rent proration calculator lets you compute it both of the common ways.
Actual Days vs the 30-Day Banker’s Month
The two methods give different daily rates for the same rent:
- Actual days: $1,800 rent in September (30 days) = $60/day; in February (28 days) = $64.29/day; in August (31 days) = $58.06/day.
- 30-day banker’s month: always $1,800 ÷ 30 = $60/day, every month.
Which favors you depends on the month. In a 31-day month, the banker’s method charges slightly more per day but bills at most 30 days; in February it charges less per day than the calendar method. The gap on a mid-month move-in is usually under $40 on $1,800 rent — but for expensive units or month-long disputes it adds up, so check which method your lease names before you sign.
Example: $1,800 Rent, Moving In September 20
Say rent is $1,800 per month and you move in on September 20.
Actual-days method: September has 30 days, so the daily rate is $1,800 ÷ 30 = $60. You occupy September 20–30, which is 30 − 20 + 1 = 11 days. Prorated rent: 11 × $60 = $660.
Banker’s method: identical here, because September happens to have exactly 30 days — $660 either way.
Now move the same scenario to August 20 (31 days). Actual days: $1,800 ÷ 31 = $58.06/day × 12 days = $696.77. Banker’s method: $60/day × 11 billable days = $660. The choice of method changes the bill by $36.77.
Frequently Asked Questions
How do you prorate rent?
Divide the monthly rent by the number of days in the month to get a daily rate, then multiply by the days you occupy the unit, including the move-in day. Example: $1,500 rent, moving in on the 10th of a 30-day month = $50/day × 21 days = $1,050. Some leases use a flat 30-day month instead.
How much is prorated rent if I move in on the 15th?
Roughly half a month. In a 30-day month you occupy 16 days (the 15th through the 30th), so on $1,800 rent you owe 16 × $60 = $960. In a 31-day month it is 17 days × $58.06 = $987.10. The exact figure depends on the month length and the proration method in your lease.
Do landlords have to prorate rent?
Usually no law requires it — proration is a matter of the lease agreement in most U.S. states. In practice nearly all landlords prorate a mid-month move-in because charging full rent for days you cannot occupy invites vacancy and disputes. Get the prorated amount and the method (actual days vs 30-day month) in writing before signing.
Is prorated rent based on 30 days or actual days?
Either — both methods are common. The actual-days method divides rent by the real length of the month (28–31 days); the 30-day “banker’s month” divides by a flat 30 for every month. Your lease should name the method. The difference is a few dollars per day and matters most in February and 31-day months.
Is prorated rent paid for the first or second month?
Most landlords collect a full first month’s rent plus deposit at signing, then prorate the second month if you moved in mid-month — but many simply prorate the first month instead. Both are legitimate; the lease dictates the arrangement. Prorating the second month protects the landlord against early default while still crediting your partial occupancy.