How to calculate prorated rent (3 methods, with Excel formulas)
If you move in or out in the middle of a month, you usually do not pay the full month's rent. You pay prorated rent: only the days you actually rent the place.
The idea is simple. The catch is that there is more than one way to work out the daily rate, and the methods give different answers.
In this article:
- the three common ways to prorate rent
- a worked example for each
- Excel and Google Sheets formulas
- what to check in your lease
Step 1: count the days
Count the days you pay for, including both the first and the last day.
Example: you move in on October 21. October has 31 days, so you pay for October 21 to 31, which is 11 days (31 − 21 + 1).
Step 2: pick the method your lease uses
| Method | Daily rate | Notes |
|---|---|---|
| Days in that month | rent ÷ days in the month (28 to 31) | The daily rate changes from month to month |
| 30-day month | rent ÷ 30 | The daily rate is the same every month |
| 365-day year | rent × 12 ÷ 365 | A yearly average daily rate |
There is no single rule that every landlord follows. The method is set by your lease or by your landlord or property manager.
Worked example: $1,500 rent, move in on October 21
- Days in that month: $1,500 × 11 ÷ 31 = $532.258… → $532.26
- 30-day month: $1,500 × 11 ÷ 30 = $550.00
- 365-day year: $1,500 × 12 ÷ 365 × 11 = $542.465… → $542.47
Same apartment, same dates, and the answers differ by almost $18. In a 31-day month the 30-day method costs you more. In February it costs you less.
Moving out
For the month you move out, count from the 1st of the month to your last day.
Example: you move out on November 15. November has 30 days, so you pay for 15 days: $1,500 × 15 ÷ 30 = $750.00. Here the "days in that month" and "30-day" methods give the same answer, because November has 30 days. The 365-day year method gives $1,500 × 12 ÷ 365 × 15 = $739.726… → $739.73.
Some leases do not prorate the last month at all, or require notice a set number of days before you leave. Check the notice and move-out terms before you pick a date.
Spreadsheet formulas (Excel and Google Sheets)
Put the monthly rent in B1, the first day in B2 and the last day in B3 (both in the same month).
Days: =B3-B2+1
Days in that month: =ROUND(B1*(B3-B2+1)/DAY(EOMONTH(B2,0)),2)
30-day month: =ROUND(B1*(B3-B2+1)/30,2)
365-day year: =ROUND(B1*12/365*(B3-B2+1),2)
EOMONTH(B2,0) returns the last day of the month in B2, and DAY() of that date is the number of days in the month. ROUND(...,2) rounds to the nearest cent. Use ROUNDDOWN or ROUNDUP if your lease rounds the other way.
If your dates cross into the next month, work out each month on its own and add them up. A full calendar month is normally just the full rent.
What to check in your lease
- Proration method: look for "prorated", "per diem" or "daily rate"
- Move-in date and first payment: some landlords collect the prorated amount together with the next full month
- Notice period and move-out terms for the last month
- If it is not written down, ask your landlord or property manager which method they use before you sign
Do it in your browser
I made a free Prorated Rent Calculator. Enter the rent and the dates, choose the method and the rounding, and it splits the amount month by month. Nothing you type leaves your browser.
Prorated Rent Calculator (free)
Summary
- Prorated rent = daily rate × days you pay for (count both the first and the last day)
- Common daily rates: rent ÷ days in the month, rent ÷ 30, or rent × 12 ÷ 365
- The method comes from your lease, so check it or ask
- Work out each month separately when the dates cross a month
General information only, not legal advice. This article was drafted with the help of AI and the numbers were checked with automated tests.