Free calculator
Rent proration calculator
Work out the partial rent for a mid-month move-in or move-out — shown both common ways, because leases don’t agree on the method. The estimate is based on the rent and dates you enter.
The short answer
Last updated: July 2026
Prorated rent is the partial rent owed for a mid-month move-in or move-out. There are two common methods: actual-days (rent × days occupied ÷ days in that month) and the 30-day banker’s method (rent × days occupied ÷ 30). They give slightly different amounts, so your lease — and sometimes local rules — decides which one governs.
After the estimate:
Rent collection in AptoriaRent proration calculator
Prorate a partial month of rent.
Moving in or out mid-month? Here's the partial rent — worked out both common ways, since leases don't agree on which to use.
Full monthly rent
$
Days in the month
28
29
30
31
28 (Feb), 29 (Feb, leap year), 30, or 31 — pick the month you're prorating.
Days occupied
12
0 days
30 days
Input-driven result
Your inputs
Formula
Result below
Actual-days method
$800.00
$2,000 × (12 ÷ 30 days)
30-day (banker's) method
$800.00
$2,000 × (12 ÷ 30 days)
The two methods differ by about $0.00 here. Your lease usually specifies which one applies — check it (some states or local rules point to a method too).
Proration method comparison
Actual-days method
$800.00
30-day method
$800.00
Difference
$0.00
Estimate based on your inputs. Not a promise of results.
How it works
How this tool works.
When a tenant moves in or out partway through a month, they owe only part of the rent — but there’s more than one accepted way to split it, and the two methods rarely land on the same number.
This calculator shows both: the actual-days method (dividing by the real number of days in that month) and the 30-day “banker’s” method (always dividing by 30). Enter the full rent and the dates and compare — then let your lease decide which one governs.
Make the result useful
Rent-proration decisions
Monthly rent is the contractual recurring rent for the period.
Move-in or move-out dates define the partial occupancy period.
Proration method is the lease or jurisdiction-required calendar-day or fixed-day approach.
Days in month matters only for calendar-day methods.
Calculation lens
prorated rent = periodic rent converted under the selected method × chargeable days
Use the output as a documented scenario result, not a guarantee.
The tool does not determine the legally required method or create a notice.
Questions landlords ask
Questions about this tool and its limits.
Built by a landlord who's done every one of these jobs by hand.
Aptoria was built by an owner-operator managing a Brooklyn portfolio — the 11pm calls, the awkward rent texts, the April receipt-pile — not by a software team guessing at the problem.
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