Calculate the exact rent owed when a tenant moves in or out mid-month. Supports calendar-day, 30-day, and annual per diem methods.
Prorated rent disputes are one of the most common sources of friction between landlords and new tenants. Using a clear, consistent calculation method — and showing your work — eliminates confusion before it starts. This calculator supports all three standard proration methods so you can use whichever your lease agreement specifies or your state requires.
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Prorated rent is the partial rent amount charged when a tenant occupies a rental property for only part of a month. Instead of paying a full month's rent for a period they didn't fully occupy, the tenant pays only for the days they were actually in the unit. It's a standard, fair practice that protects both parties.
Proration is most commonly needed when a tenant moves in after the 1st of the month, when a tenant moves out before the last day, or when a lease renewal doesn't align with the first of the month.
Calendar Day Method — Divide monthly rent by the actual number of days in that month (28, 29, 30, or 31), then multiply by the number of days occupied. This is the most accurate and most widely used method.
30-Day Standard Method — Always divide by 30 regardless of the actual number of days in the month. Simpler and more predictable, but slightly less accurate in longer or shorter months.
Annual Per Diem Method — Divide the annual rent (monthly × 12) by 365 to get a daily rate. Best used for mid-year lease starts or when the lease specifies this method.
Tenant moves in on the 15th of June (30-day month). Monthly rent is $1,500. Using the calendar method: 16 remaining days ÷ 30 days × $1,500 = $800.00 due. Using the 30-day method: same result. Using the annual method: ($1,500 × 12 ÷ 365) × 16 days = $789.04 due.
Most states do not legally require landlords to prorate rent, but it is widely considered standard practice and a tenant may negotiate for it. If your lease specifies a start date mid-month at the full monthly rate, that is technically legal in most jurisdictions — but it may deter good tenants. Prorating is the professional and fair approach.
For the calendar day method in a leap year, use 29 days for February. This calculator uses standard 28-day February — adjust manually for leap years if needed, or use the 30-day standard method to avoid the variation entirely.
Yes — the same logic applies when a tenant moves out before the last day of the month. Using the move-out option in this calculator, enter the day they vacate and it will calculate what they owe for the days occupied that month.