Prorated Rent Calculator
Rent & days
Your result will appear here
Fill in the fields on the left and this updates as you type.
Know what this estimate is based on
- Jurisdiction
- United States — state and local practice
- Scope and limitations
- Educational estimate only. U.S. real estate costs are local: property tax rates, transfer and recording taxes, title practice, who customarily pays which closing cost, and landlord-tenant rules all change by state and often by county or city. Agent commission is negotiable and, since the 2024 NAR settlement, buyer-agent compensation is negotiated separately rather than assumed. Only a lender's Loan Estimate, a title company's fee sheet or a signed contract binds a number.
- Source links checked
- Jul 30, 2026
Built and regression-tested by Smart Tools Lab. It has not been individually reviewed by a licensed financial, tax, or legal professional.
How to use
- 01
Enter the full monthly rent from the lease, not the prorated amount you were quoted.
- 02
Enter how many days you actually occupy the unit this month, counting the move-in day.
- 03
Set how many days this month has. It is the divisor, so it decides the answer.
- 04
Read the three figures. They are all legal conventions and they disagree — the spread tells you how much is at stake.
- 05
Open Advanced options to match the divisor your lease actually names, if it names one.
Formula
Three conventions, one day count. Actual days: monthly rent / days in this month x days occupied. Flat 30: monthly rent / 30 x days occupied, or whichever divisor the lease names. Annualized: monthly rent x 12 / days in the year x days occupied. The day count is clamped to the length of the month, because a lease cannot charge for more days than the month has — a full month is a full month's rent, and proration only applies to a partial one. All three divisors keep their defaults rather than opening blank: a zero divisor is not an empty field, it is a division by zero.
Example
A $1,900 rent, moving in for the last 13 days of a 31-day month. Actual days: $1,900 / 31 = $61.29 a day. x 13 = $796.77. Flat 30: $1,900 / 30 = $63.33 a day. x 13 = $823.33. Annualized: $1,900 x 12 / 365 = $62.47 a day. x 13 = $812.05. The spread is $26.56 for exactly the same thirteen days — about 3.3% of the bill. All three are legal, and which one you pay depends entirely on a clause most people never read. Note the direction. In a 31-day month the flat-30 method is the dearest, because it divides by fewer days than the month has. In February the same clause works the other way: $1,900 / 30 is cheaper per day than $1,900 / 28. A landlord who uses flat-30 all year is not gaming you; a landlord who switches methods by month is.
Definitions
- Prorated rent
- Rent charged for part of a month, based on the days you actually occupy the unit.
- Actual-days method
- Monthly rent divided by the days in that specific month, times the days occupied. The most defensible default.
- Flat-30 method
- Monthly rent divided by 30 regardless of the month's real length. Cheaper in February, dearer in a 31-day month.
- Annualized method
- Rent x 12 divided by the days in the year, times the days occupied. Consistent across months, sometimes called the banker's year.
- Daily rate
- The per-day cost under whichever convention is used. The whole disagreement between the methods lives here.
- Divisor
- The number of days the monthly rent is divided by. Naming it is the single most useful thing a lease can do here.
- Move-in date
- The day your right to occupy begins. Normally counted as a full day of rent.
- Lease term
- The period the lease covers. A prorated first month usually sits outside it, with the full term starting the following month.
- Banker's month
- A 30-day month used for convenience in calculations, regardless of the calendar.
- Rent commencement
- The date rent starts accruing, which is not always the date you get the keys.
- Partial month
- Any month you occupy for fewer than all its days, at either end of a tenancy.
- Property tax proration
- Splitting a year's property tax between buyer and seller at a closing. A different calculation from this one.
Good to know
Three lawful methods, three different bills
There is no single national rule for prorating rent, so leases pick a convention and the conventions disagree. The actual-days method divides the monthly rent by the number of days in that specific month — 31 in July, 28 in February — which makes the daily rate move month to month. The flat-30 method always divides by 30 regardless of the calendar, which is the banker's convention and the most common in professionally managed buildings. The annualized method multiplies the rent by twelve, divides by 365, and produces a rate that never changes. On $1,900 of rent for 13 days of a 31-day month, they ask $796.77, $823.33 and $812.05 respectively. The $26.56 spread is not a rounding difference or an error — it is three defensible answers to the same question, and which one applies is whatever your lease says.
Why the flat-30 method usually costs the tenant more
Dividing by 30 in a 31-day month makes each day slightly more expensive than it really is, because you are charging 1/30th of the rent for 1/31st of the month. Over 13 days that is $26.56 in the landlord's favour. In a 28-day February the arithmetic reverses and the flat-30 method is cheaper for the tenant, but the calendar is not symmetric: seven months have 31 days, four have 30, and one has 28 or 29. Averaged over a year the flat-30 convention collects slightly more than the rent, which is why it is the industry standard and why it is worth reading the proration clause rather than assuming. On a single move this is a modest amount. On a portfolio of several hundred units with normal turnover, it is a line item.
Prorating the move-out, and what it does not cover
The same arithmetic applies at the other end, with one difference that catches people: notice periods run from the notice date, not from the month boundary. A lease requiring 30 days' notice given on the 10th generally obligates you through the 9th of the following month, and you owe prorated rent for those days even if you moved out on the 15th. Some leases go further and require notice to expire at month end, which converts a mid-month move into a full month of rent. Neither is unusual and neither is negotiable after signing. The other thing proration does not cover is the fees: parking, pet rent, amenity charges and utility allocations are often charged whole regardless of how many days you occupied. Ask which recurring charges prorate and which do not, because the answer is frequently different for each one.
Where state law does have something to say
Prorated rent is mostly a matter of contract rather than statute, but several states constrain the edges. A number require that any late fee be reasonable and disclosed, which limits how a landlord treats a disputed proration. Some jurisdictions require rent receipts on request. And a handful of cities with rent stabilisation define the daily rate for regulated units directly, removing the choice of convention. The practical rule is simpler than the legal landscape: get the number in writing before the keys change hands, in the lease or in a signed addendum. A prorated amount agreed by text message and then disputed is a small claim you will probably win and definitely resent. If the lease is silent on the method, propose the actual-days figure in writing — it is the most defensible, since it charges for the days that actually exist.
This is not the tax proration on a home sale
The word proration appears in two unrelated places in US real estate and they are easy to confuse. Rent proration splits one month's rent between two occupancy periods. Tax proration splits the year's property tax between a buyer and a seller at closing, and it works on a completely different basis — commonly a 365-day year, sometimes a 360-day year, and in several states against a tax bill that arrives in arrears for a period that has already passed. Getting the two mixed up matters because the settlement statement at a closing frequently contains both a rent proration line, if the property has tenants, and a tax proration line, and they will not use the same convention. If you are buying an occupied rental, check each line separately against the lease and against the county's billing cycle.
Frequently asked questions
Which method is correct?
Whichever your lease names. All three are used in the US and none is universally required. If the lease is silent, the actual-days method is the one a court is most likely to call reasonable, because it charges you for the share of the month you actually had.
Why does the flat 30-day method cost more?
Because in a 31-day month it divides by fewer days than the month contains, making each day slightly more expensive. Move in on the 19th of a 31-day month and the flat-30 method charges you for 13 days at a 30-day rate — which is why a lease saying "divided by 30" quietly favours the landlord in long months.
What is the annualized method?
Rent times twelve, divided by the days in the year, times the days you occupy. It smooths out the difference between long and short months, so February stops being cheaper per day than March. Some property managers use it precisely for that consistency.
Do I count the day I move in?
Almost always yes — you have the keys and the right to occupy, so it counts. The day you move out is usually counted too if the lease runs through it. Read the lease, because a day either way is real money at the daily rate.
Is prorated rent required by law?
Not federally, and rarely by state law for a mid-month move-in. It is a matter of the lease and of custom. That said, almost every landlord prorates a move-in, because charging a full month for eleven days is the kind of thing that ends up in a review.
What about my last month?
The same arithmetic applies at the other end, though many leases require you to pay a full final month and give notice covering it. If you paid last month's rent at move-in, check whether that payment is applied to a full month or prorated.
Can the landlord pick whichever method costs me more?
If the lease names a method, that governs. If it does not, there is nothing stopping them proposing one — which is why it is worth reading the clause before signing rather than arguing after the invoice.
Do fees get prorated too?
Usually yes for recurring charges — pet rent, parking, amenity fees — and usually no for one-off fees like the application or admin fee. The Move-In Cost Calculator handles the whole bill.
What if the numbers are close?
Then it is not worth the argument. A $27 spread on a $1,900 rent is real, but not worth a difficult start with a landlord you will deal with for a year. The number is there so you can decide, not so you have to fight.
Is this the same as property tax proration?
No. This splits one month's rent between a tenant and a landlord at move-in. Property tax proration splits a year's tax between a buyer and a seller at a closing — a different calculation with different customs.
Does February change the answer?
Substantially. On a 28-day month the actual-days rate is higher than the flat-30 rate, so the usual advantage reverses. That is exactly why leases name a divisor rather than leaving it to the calendar.
Why is there no date picker?
Because a day count and a month length produce exactly the same answer, and a number you type is easier to check than a date you selected. Enter the days and the arithmetic is transparent.