Prorated Rent Calculator
Work out exactly what a tenant owes when they move in or out partway through the month — and see how much the daily-rate method you choose changes the answer.
Move-in rent due for August 2026
$2,400.00
31 of 31 days at $77.42/day
Charging from the 1st through the 31st (both days included).
The full rent the lease specifies for a complete month.
The first day the tenant has the keys.
What the method choice is worth
| Method | Daily rate | Rent due |
|---|---|---|
| Actual days in monthselected | $77.42 | $2,400.00 |
| 30-day month | $80.00 | $2,400.00 |
| 365-day year | $78.90 | $2,400.00 |
Check your lease — many specify the method, and some states require a particular one. Where the lease is silent, actual days in the month is the most widely accepted default.
Breakdown
How prorated rent works
Prorating rent is simple division: take the monthly rent, work out a daily rate, then charge for the days the tenant actually holds the unit. A tenant taking keys on the 20th of a 31-day month occupies 12 days — the 20th through the 31st, counting both — so they owe 12 daily rates rather than a full month.
The part that causes disputes is which daily rate. The same $3,000 rent produces a daily rate of $96.77 if you divide by a 31-day January, $107.14 if you divide by a 28-day February, $100.00 if you always divide by 30, and $98.63 if you divide the annual rent by 365. On a two-week partial month those spreads are worth real money, which is why the calculator shows all three side by side and why your lease should name the one you use.
Which method should you use?
For residential leases, actual days in the month is the most defensible default: the tenant pays precisely for the days they had the unit, and no month subsidizes another. It is also the method a court or housing authority is most likely to consider reasonable if the lease is silent.
The 30-day method trades that precision for predictability, which is why commercial leases and most property-management software use it. It slightly overcharges in 31-day months and undercharges in February. The 365-day method smooths the daily rate across the entire year, producing a middle figure that never varies by month. Any of the three is fine — being inconsistent between tenants is not.
What not to prorate
Only rent gets prorated. The security deposit is a fixed sum held against damage and unpaid rent, so it doesn’t scale with a partial first month, and one-time move-in fees generally don’t either. Recurring monthly add-ons — parking, pet rent, storage — usually do get prorated on the same basis as the rent, since they cover the same partial occupancy period. Spell out which is which in the lease so the first invoice isn’t a surprise.
Frequently asked questions
Educational tool only. Proration rules can be set by your lease and, in some jurisdictions, by state or local law — check both before billing. Not legal advice.