When a tenant moves in or out mid-month, you charge for the days they actually had the keys — not the whole month. Enter the numbers below; the calculator shows both common proration methods so you can match your lease.
Actual days in month: rent ÷ days in the month × days occupied. This is the most accurate and the most common in residential leases. 30-day month (banker’s method): rent ÷ 30 regardless of the month — simpler, slightly different numbers in February vs. July.
Your lease controls. If it says nothing, actual-days is the fair default and the harder one to argue with.
Moving in: charge for the remaining days including the move-in day. Moving out: charge for days through the move-out date. Set the direction above — the math mirrors.
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It depends on the lease and state law — many leases address it, and a few states require it. When in doubt, prorating is the defensible, good-faith default.
Your lease decides. Actual-days is more precise; the 30-day method is simpler and slightly favors the landlord in 31-day months. This calculator shows both.
Yes — 10Doors computes prorated charges for mid-month move-ins and lease changes automatically, so you never do this math by hand after signup.
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Manage your property free on 10DoorsThis template is provided for general informational purposes and does not constitute legal advice. Landlord-tenant law changes and local ordinances may impose additional requirements — verify current state and local rules before serving any notice. Last reviewed September 2026.