Prorated Rent Calculator

Calculate one billing month’s partial rent using an explicit daily-rate method and date convention. Use the method agreed for the tenancy; this calculator does not decide what is legally owed.

CurrencyUse one currency for all amounts. This changes labels only; it does not convert money or change local rules.

Monthly rentUSD

Daily-rate methodMethods can give different answers. Fixed-divisor modes do not cap the calculated amount at one month’s rent.

First chargeable dateStart date is included. Use one billing month per calculation.

End dateThe selector below decides whether this date is charged.

Is the end date charged?Choose according to the actual agreement. Neither convention is assumed to be legally required.

Amount already paid toward this chargeUSDOptional arithmetic reconciliation only. A negative balance is not a ruling that a refund is legally due.

Calculation results

Calculated partial-month rent

—

How to use this calculator

Choose the daily-rate basis

Actual-days mode uses the number of days in the billing month. The other modes deliberately use fixed divisors of 30 or 365; do not assume the methods are interchangeable.

Choose the dates and boundary

The first date is charged. Select whether the last date is charged or represents an exclusive checkout boundary. For example, an exclusive October 1 endpoint can cover September through September 30.

Keep chargeable days in one month

The calculator rejects intervals containing charged days in different months. Split those intervals by billing month so the denominator and agreement remain explicit.

Review before reconciling

The daily rate is not rounded before multiplication. The final charge is rounded to two decimals, then an entered payment is subtracted for a simple balance.

Formula and worked example

Inclusive day count = end date − start date + 1 calendar day
Exclusive-end day count = end date − start date
Actual-month daily rent = monthly rent ÷ actual days in billing month
Fixed-30 daily rent = monthly rent ÷ 30
Annual-365 daily rent = monthly rent × 12 ÷ 365
Charge = round to two decimals(daily rent × chargeable days)
Arithmetic balance = charge − amount already paid

For monthly rent of 1,500 and September 16–30 with both dates charged, the day count is 15. September has 30 days, so actual-days rent is 1,500 ÷ 30 × 15 = 750. Excluding September 30 gives 14 days and 700. For the original 15-day period, annual-365 mode instead gives about 739.73.

The divisor changes a 15-day partial-month charge

Illustrative arithmetic, not a recommendation of a lease term or legal method. Dates must produce the stated count in one billing month.
Monthly rent 1,500	Daily rate before rounding	Charge for 15 days
Actual month with 30 days	50	750.00
Actual month with 31 days	48.387096…	725.81
Fixed annual ÷ 365	49.315068…	739.73

Frequently asked questions

Which proration method should I use?

Use the method and day-count convention applicable under the agreement and any controlling rules. The calculator shows arithmetic choices; it does not decide whether proration is required or which method is enforceable.

Does it handle leap-year February?

Yes. Actual-days mode uses the real calendar month, including 29 days in leap-year February. Annual-365 mode always divides by 365, even in a leap year, because that is the explicitly selected convention.

Why can fixed-30 mode exceed monthly rent?

It multiplies monthly rent divided by 30 by the actual charged-day count, without a cap. Charging all 31 days of a 31-day month therefore gives 31/30 of monthly rent. Do not use that result unless it matches the intended arrangement.

Can the end date be the first of the next month?

Yes, when the end date is excluded and every charged day remains in the start month. An inclusive end date in the following month spans two billing months and must be split.

Why might a manual result differ by a few cents?

This tool multiplies using the unrounded daily rate, then rounds the final charge to two decimals. Rounding each daily rate first, or applying another currency/contract convention, can change the result.

Methodology and sources

One billing month and one monthly rent amount, with dates from 1900 through 2100. Counts calendar days rather than local elapsed hours, avoiding daylight-saving differences. Excludes deposits, fees, concessions, tax, late charges, rent changes and legal determinations. The two fixed-divisor methods are uncapped; a negative payment balance is only an arithmetic excess payment.

Zillow — prorated rent calculation — Actual-month daily rent multiplied by occupied days.
RentSpree — proration methods — Examples of actual-month, fixed-30 and annual-365 arithmetic. The calculator makes its own date-boundary and rounding conventions explicit.

Sources checked September 1, 2026. Referenced organizations do not endorse Efficienco. The final charge is rounded once to two decimals, not the daily rate. Charges and balances use nearest-cent rounding, with exact half-cent ties away from zero. Different currency or lease rounding conventions may require a different calculation.