Prorated Rent Calculator
Calculate prorated rent for partial month periods with precision
How this prorated rent calculator works
When a tenant occupies less than a full rental period, this tool computes the exact amount owed for the partial month by converting the monthly rent into a precise day rate and multiplying it by the number of days the unit is occupied during that billing cycle.
If the billing cutoff (the tenant’s rent due date) falls inside a different calendar month than the move-in date, the calculator handles each month separately and adds the two prorated figures together for a final total.
The method
- Convert the monthly rent into a daily rate by dividing the full monthly rent by the number of days in that specific month (for example, 28, 29, 30, or 31).
- Count the number of billable days the tenant occupies the unit that belong to that month.
- Multiply the daily rate by the billable days to get the prorated amount for that month.
- If the billing cycle spans two months, repeat steps 1–3 for the second month and sum the two results.
Why we calculate per calendar month
Different months have different lengths, and that changes the daily rent. By computing the per-day price for each affected month separately we avoid small but real errors that can accumulate if you used a single fixed month length.
Simple examples
Example Billing on the 1st (single month):
- Monthly rent: $1,000
- Move-in: August 20 (August has 31 days)
- Daily rate: 1000 ÷ 31 = 32.2580645161… (we keep extra precision internally)
- Billable days in August: 31 − 20 + 1 = 12 days
- Prorated rent (August): 32.2580645161 × 12 = 387.0967741932 → $387.10 (rounded to cents).
Example Billing on a date other than the 1st (spans two months):
- Monthly rent: $1,000
- Move-in: August 20 (31 days in August)
- Rent due date: September 15 (September has 30 days)
- August daily rate: 1000 ÷ 31 = 32.2580645161… → billable days = 12 → August amount ≈ 387.0968
- September daily rate: 1000 ÷ 30 = 33.3333333333… → billable days = 14 (1st–14th) → September amount ≈ 466.6667
- Total prorated rent ≈ 387.0968 + 466.6667 = 853.7635 → $853.76 (final amount rounded to cents).
Edge cases you should be aware of
- Leap year: February can have 28 or 29 days – the daily rate will adjust accordingly.
- Rent due date on the 29th/30th/31st: If the due date doesn’t exist in a shorter month, calculations move to the calendar convention your lease follows (our calculator aligns with the common practice of using the last day of that month when needed).
- Partial-day move-ins: Most landlords charge by calendar day (not hours). If you want hourly proration you’ll need a different policy stated in the lease.
Practical tips for landlords and tenants
- State it in the lease: Specify the proration method (per-calendar-month day rate) and the rent due date. That prevents confusion.
- Show the math: Provide the tenant with the daily rate, billable days, and the monthly breakdown, transparency reduces disputes.
- Automate where possible: Using a small embedded calculator like this eliminates manual mistakes and speeds move-in processing.
FAQs
Q1. Do you always divide by the number of days in the calendar month?
A: Yes. The fair approach is to use that month’s actual day count so each daily rate reflects the real length of the month.
Q2. How are partial cents handled?
A: Intermediate computations keep high precision. The total payable is rounded to the nearest cent; the daily rate may be displayed with extra decimals for clarity.
Q3. What if a lease defines a different proration method?
A: The lease controls. If your contract specifies a unique approach (for example, dividing by a fixed 30 days), follow what’s written; otherwise use the calendar-month method used here.