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To calculate prorated rent, find a daily rate and multiply it by the number of days the tenant occupies the unit in that month. The most common method divides the monthly rent by the number of days in that month: $1,500 rent in a 30-day month is $50 a day, so a tenant moving in on the 21st owes 10 days, or $500. Other methods divide by 365 or by a 30-day "banker's month." Whichever you use, put it in the lease so the math is never a surprise.
This guide shows each method with worked examples, covers move-ins, move-outs and mid-month rent changes, and explains how to write the proration clause.
The three methods
| Method | Daily rate | Example: $1,500 rent, move-in Sept. 21 (10 days) |
|---|---|---|
| Days in the month | Monthly rent ÷ days in that month | $1,500 ÷ 30 = $50.00 × 10 = $500.00 |
| 365-day year | Monthly rent × 12 ÷ 365 | $18,000 ÷ 365 = $49.32 × 10 = $493.15 |
| 30-day (banker's) month | Monthly rent ÷ 30, every month | $1,500 ÷ 30 = $50.00 × 10 = $500.00 |
The methods match in a 30-day month and differ in 28-, 29- and 31-day months:
| Month | Days in the month | 365-day year | 30-day month |
|---|---|---|---|
| February (28 days), 10 days owed | $535.71 | $493.15 | $500.00 |
| October (31 days), 10 days owed | $483.87 | $493.15 | $500.00 |
The differences are small, but they're the kind tenants notice. Pick one method and use it every time.
All figures are hypothetical. Our prorated rent calculator runs all three methods for any rent and dates.
Counting the days
Count both the first and last day the tenant has the unit. A move-in on September 21 in a 30-day month covers September 21 through 30: that's 10 days, not 9. A quick check: days owed = days in the month − move-in day + 1.
For a move-out, count from the 1st through the last day of the tenancy. A tenancy ending October 12 covers 12 days in October.
Move-in mid-month
Two common ways to handle the first partial month:
- Collect the prorated amount at move-in, then full rent on the 1st of the next month. Simple, and rent is due on the 1st from then on.
- Collect the prorated amount plus the next full month at move-in. Useful when a tenant moves in late in the month, so you're not collecting two payments a few days apart.
Example of option 2: $1,500 rent, move-in September 25. September 25 to 30 is 6 days, or $300 by the days-in-month method. The tenant pays $1,800 at move-in, covering September 25 through October 31, and full rent is due November 1.
Spell out whichever you choose in the lease.
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Move-out mid-month
Whether a tenant who leaves mid-month gets prorated rent back depends on your lease and state law. A tenant who leaves before a fixed-term lease ends is a different situation, covered in lease early termination fees. If the tenancy legitimately ends mid-month, for example by a notice to vacate dated for the 15th, prorate the final month.
Show the proration on the deposit statement if you deduct unpaid rent: period, daily rate, days owed, amount paid, balance. How to return a security deposit covers the statement.
Rent changes mid-month
If a rent increase or a lease amendment takes effect mid-month, prorate the old rent for the days before the change and the new rent for the days after:
October: rent rises from $1,500 to $1,560 on October 16. Days-in-month method: 15 days × ($1,500 ÷ 31) = $725.81, plus 16 days × ($1,560 ÷ 31) = $805.16. Total $1,530.97.
Most landlords avoid this by making changes take effect on the 1st. If you're raising rent, also check your state's notice rules on the rent increase laws hub.
Rounding
Round to the cent at the end, not on the daily rate. With $1,500 ÷ 31 = $48.387…, 10 days is $483.87, while rounding the daily rate first gives $483.90. Pick a rule and keep it consistent.
Put it in the lease
A short clause prevents arguments:
If the tenancy begins or ends on a day other than the first or last day of a month, rent for that month will be prorated by dividing the monthly rent by the number of days in that month and multiplying by the number of days of occupancy, rounded to the nearest cent.
The lease agreement generator includes the start date and first payment amount, and a rent receipt for the prorated payment should show the dates it covers.
A note on taxes
Prorated rent is rental income like any other rent. If you collect rent in advance, such as a full month plus the prorated amount at move-in, the IRS treats advance rent as income in the year you receive it (IRS Topic 414, Rental income and expenses).
Sources
Official source cited above (checked 2026-10-28):
Frequently asked questions
What is the most common way to prorate rent?
Divide the monthly rent by the number of days in that month and multiply by the days the tenant occupies the unit. For $1,500 in a 30-day month, that's $50 a day, so 10 days costs $500.
Do you count the move-in day when prorating rent?
Yes. Count both the first and last day of occupancy, so a September 21 move-in covers 10 days in September, not 9.
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