Prorated rent calculator for a mid-month move

When is rent prorated?

Rent is prorated when you pay for only part of a month: you move in after the 1st or move out before the last day. The amount is the monthly rent multiplied by the part of the month you live there, which is what prorated rent means. Whether a landlord prorates at all, and by which method, is set by the lease, so this page covers the arithmetic only.

How do you calculate prorated rent?

1. Count the days you pay for. Moving in on day D of a month with N days, you pay for N minus D plus 1 days, because the day you move in counts. Moving out on day D, you pay for D days.
2. Pick the method. The actual-day method divides the rent by the real number of days in the month. The 30-day method divides it by 30 every month and never charges for more than 30 days.
3. Multiply. The daily rate times the days you pay for is the prorated rent.

Take $1,800 rent and a move-in on the 12th of a 31-day month. That is 31 minus 12 plus 1 = 20 days. On actual days, $1,800 ÷ 31 is $58.0645 a day (shown as $58.06), and 20 days at that unrounded rate comes to $1,161.29. On a 30-day month, $1,800 ÷ 30 is $60.00 a day, and 20 days comes to $1,200. The 30-day method costs $38.71 more here.

In the calculator, type 1 in the “Moving in (1) or moving out (2)” box to count from your move-in day to the end of the month, or 2 to count from the 1st to your move-out day. It shows amounts of $1,000 or more in whole dollars, so this example reads $1,161 and $1,200 on screen.

Which method gives the lower amount?

For a part month, the 30-day method costs more than actual days in a 31-day month and less in a 28-day month. In a 30-day month the two are the same. These amounts are for $1,800 rent:

Move	Days you pay for	Actual days	30-day month
In on the 12th, 31-day month	20	$1,161.29	$1,200.00
Out on the 12th, 31-day month	12	$696.77	$720.00
In on the 12th, 30-day month	19	$1,140.00	$1,140.00
In on the 12th, 28-day month	17	$1,092.86	$1,020.00

The lease or the landlord says which one applies. If neither does, ask before you pay and write the answer down.

What happens when one roommate leaves and another arrives?

Use the actual-day method for a handover, so the two shares add up to the rent. Say one roommate moves out on the 12th and the next moves in on the 13th of a 31-day month. The first pays for 12 days ($696.77) and the second for 19 days ($1,103.23), which add up to exactly $1,800.

On the 30-day method the same handover comes to $720 and $1,140, which add up to $1,860, or $60 more than the rent. If your agreement counts every month as 30 days, the two roommates can still agree to use actual days for the handover month so the shares add up. For the other money questions when someone leaves early, see what roommates owe each other when one moves out early.

Common mistakes

• Forgetting the move-in day. Subtracting 12 from 31 gives 19 days and $1,103.23, which is $58.06 less than the correct $1,161.29.
• Using 30 for every month out of habit. In a 31-day month that can cost $38.71 more, as above. Check the lease first.
• Prorating the bills with the rent. Utilities run on their own billing period, so split them by the days each person was home with the utility bill split calculator.

A prorated first month is a one-off amount. In EvenOut it is a normal expense. When the first full month comes, add the rent with Repeat set to Monthly, and each later month adds itself. If the rent changes at the same time, how to split a rent increase between roommates shows how to share the new amount, and everything on the topic sits under roommates and rent.