How to Prorate Rent When Moving Out, With the Math Shown

Prorated rent on a move-out is rent for only the days you still have the unit: the monthly rent, divided by the days in the month, times the days from the 1st through your move-out day. Moving out on October 18 with rent of $1,650, that is $958.06. Whether you get to pay it instead of the full month depends on your lease, your state and your landlord.

The formula

Prorated rent = monthly rent ÷ days in the month × days you have the unit

For a move-out, count from the 1st of the month through the move-out day, both included. Out on the 18th is 18 days. Out on the 1st is one day.

The only real question is the daily rate, because leases divide the month in one of three ways.

Three ways to divide the month

Rent is $1,650, and the tenant moves out on Sunday, October 18, 2026, keeping the unit for 18 of October’s 31 days.

Actual days in the month: $1,650 ÷ 31 = $53.23 a day. For 18 days, $1,650 × 18 ÷ 31 = $958.06.

30-day month (banker’s month): $1,650 ÷ 30 = $55.00 a day. For 18 days, $990.00.

365-day year: $1,650 × 12 ÷ 365 = $54.25 a day. For 18 days, $976.44.

The spread is $31.94 on a single move. In a 31-day month, actual days costs the tenant least and the 30-day month costs the most. In February it flips, and actual days costs the most, because the same rent is spread over 28 days.

The lease picks the method. When it says nothing, actual days in the month is the most common choice, and landlord and tenant can agree on one in writing. The prorated rent calculator shows all three side by side, with each step written out.

When a move-out can be prorated

The math is easy. The right to use it is not automatic, and three things decide it.

1. Your lease. A fixed-term lease that ends on the 14th already prorates its last month: you owe rent through the 14th. A lease that ends on the 31st is different. Leave on the 18th and you still owe the whole month, because moving out early does not shrink what you agreed to pay.
2. The rules for ending a month-to-month tenancy. In some states and under many leases, a month-to-month tenancy can end only on the last day of a rental period. There, a notice that runs out mid-month still leaves the full last month owed. Where a tenancy can end on any day after proper notice, the end date can fall mid-month, and the last month is prorated. The notice to vacate by state table shows how much notice each state asks for.
3. Your landlord. Even where neither the lease nor the law requires it, many landlords will prorate, especially when the next tenant can move in sooner. Get the yes in writing, with the amount.

A move-out, start to finish

Priya rents month to month at $1,650, due on the 1st, in a state that lets a tenancy end on any day after 30 days’ notice. She gives written notice on Monday, October 19, 2026, for a move-out on Wednesday, November 18.

November has 30 days, and she keeps the unit for 18 of them: $1,650 × 18 ÷ 30 = $990.00. On November 1 she pays $990 instead of $1,650, and keeps $660.

If her lease prorates on a 365-day year instead, the figure is $976.44.

Put the move-out date in the notice itself, and name the prorated amount you expect to pay. The notice to vacate letter fills in the date and checks it against your state’s minimum notice.

Moving out a day late

The same formula runs the other way. Hand in the keys on November 1 instead of October 31, and you have had the unit for one day of November: $1,650 ÷ 30 = $55.

That assumes the landlord agrees to the extra day. Without an agreement, a tenant who stays past the end date is a holdover tenant, and some leases set a higher daily rate for holdover days. Check before you plan one.

Last month’s rent and the deposit

Two prepayments cause most move-out confusion:

• Prepaid last month’s rent. If you paid last month’s rent at move-in, it pays for the final month. If that month is prorated, the unused part should come back to you. With $1,650 prepaid and a $990 prorated November, the landlord owes you $660.
• The security deposit is not rent. Don’t leave the final month unpaid and expect the security deposit to cover it. Many leases forbid it, it can start late fees, and the landlord may need the deposit for damage. The deadline to return the deposit runs from move-out; the security deposit limits by state table lists each state’s.

For landlords: prorating fairly

If you prorate, use the method the lease names, and use it both ways: at move-in and at move-out. A tenant charged on a 30-day month when moving in on October 12 and on actual days when moving out on October 18 will notice. When the lease is silent, pick one, write it into the move-out agreement and show the math. It turns a possible dispute into a one-line receipt.

Three mistakes that cost money

• Dropping a day. A move-out on the 18th is 18 days, not 17. Subtracting the 1st from the 18th loses the first day of the month.
• Using the wrong month. The days are the move-out month’s: 30 for November, not the 31 of the October before it.
• Paying before the number is agreed. Sending $990 on November 1 with no agreement in place invites a late fee on the other $660. Settle the amount first, then pay it on the due date.

Get it in writing

Before the keys change hands, keep one short written record: the move-out date, the method, the prorated amount and when it is paid. Once it is paid, ask for a receipt that shows the dates it covers. The rent receipt prints one with the amount and the period on it.