Prorated Rent Calculator

What Is Prorated Rent?

Leases are written in months; moves happen on Tuesdays. Whenever the days you hold a unit do not line up with the period the lease bills for, someone has to convert a month into days, and prorated rent is the result of that conversion.

The daily rate, and the days you are charged for

A prorated bill has exactly two moving parts. The daily rate is the monthly rent divided by a divisor — either the number of days in that particular calendar month, or a flat 30. The day count runs from your move-in date through the last day of the month, or from the 1st through your move-out date.

Both conventions charge for the move date itself. California's Department of Transportation writes the rule into its own tenancy paperwork in one line: include the start date in the number of days counted, and include the vacate date when a tenant is leaving. A July 20 move-in is therefore 12 days of July, the 20th through the 31st, not 11.

The same paperwork notes the case where none of this applies: if a tenancy starts on the first day of the month or ends on the last day, no proration is necessary regardless of the month's length. A full month is a full month, and the divisor never enters into it.

Which month actually gets prorated

Leases handle a mid-month start in one of two ways. The first prorates the opening month, so a July 20 move-in pays for 12 days of July and then a normal full rent on August 1. The second collects a full month's rent at signing and prorates a later month instead, so that the payment cycle settles onto the 1st.

The money is the same under either pattern. Across July 20 to August 31 you are paying for 43 days — 12 prorated days at $580.65 plus a full August at $1,500.00, which is $2,080.65 on a $1,500 rent. What changes is which check is the short one, and that is worth knowing before you budget the move.

Ask which pattern applies before signing, because the two produce very different first payments. One asks for $580.65 at the door; the other asks for $1,500.00 and makes a later month the short one.

What proration does not touch

A security deposit is not rent, and dividing it by days makes no sense — it is money held against damage and unpaid amounts, returned at the end. New York caps a residential deposit at one month's rent and gives the landlord 14 days after the tenant vacates to return it with an itemized statement of anything kept. Other states set their own caps and deadlines, so check the rule where you live before assuming the timing.

Fixed monthly extras are a lease question rather than a rule. Parking, storage, and pet rent are prorated in some leases and billed whole in others. Utilities can go either way too: the Caltrans schedule prorates rent and utilities together on the same daily basis where they apply, which is a reasonable model to ask for but not something you can assume.

Weighing the whole cost of renting against owning the same space? Put the other side of that comparison through the Mortgage Calculator.

How Do You Calculate Prorated Rent?

One division and one multiplication. All of the difficulty sits in choosing the divisor and counting the days correctly — the arithmetic itself is a single line.

The prorated rent formula, written out

Daily rate = monthly rent ÷ divisor
    divisor = days in that calendar month (28, 29, 30 or 31)
           or a flat 30, when the lease says so

Move-in:   days charged = days in month − move-in day + 1
Move-out:  days charged = move-out day

Prorated rent = daily rate × days charged

The +1 on the move-in line is the move date. Without it you would be counting the gaps between days rather than the days themselves, and a move-in on the last day of the month would come out as zero. The move-out line needs no adjustment because the count starts on the 1st, so the date number and the day count are the same thing.

Round once, at the end. Rounding the daily rate before multiplying shifts the total slightly — never by much, at most around fifteen cents over a 31-day count, since each day can only be off by half a cent. It is still enough for two people with calculators to disagree about a figure.

Step by step

Working it by hand, in the order that avoids mistakes:

• Find the divisor. Read the lease first. If it names a flat 30-day month, use 30. If it says nothing, use the number of days in the month the move falls in — 28, 29, 30 or 31.
• Divide the monthly rent by that divisor and keep the decimals. $1,500 ÷ 31 is $48.3871 a day, not $48.39; the rounded version is for display.
• Count the days. Moving in: from your date through the last day of the month, inclusive. Moving out: from the 1st through your last day, inclusive.
• Multiply the unrounded daily rate by the day count, then round the answer to the nearest cent.
• Sanity-check the size of it. A partial month should never come out above one full month's rent, and roughly half a month of days should land near half the rent.

The calculator does the same five steps and shows you the middle of the working, which is the part worth comparing against the figure a leasing office sends you.

Worked example: moving in on July 20 at $1,500 a month

Set What's Happening to Moving IN, the move date to July 20, 2026, the rent to 1500, and the method to actual days. July has 31 days, so the divisor is 31 and the count runs from the 20th to the 31st.

Daily rate  = $1,500 ÷ 31 = $48.3871 a day
Days charged = 31 − 20 + 1 = 12 days (the 20th through the 31st)
Owed        = $48.3871 × 12 = $580.65

Prorated Rent Owed

$580.65

The panel prints the amount and three lines beneath it: "12 days of July 2026 (move-in on the 20th, through month end, both days counted)", then "Daily rate: $48.39 = $1,500 ÷ 31 days (actual days in the month)", then "Check the lease — it may name the proration method and whether move-in day is charged".

Switch the method to the flat 30-day month and the same move date returns $600.00, on a daily rate of $50.00. That is $19.35 more for identical occupancy, decided by nothing but which divisor the lease specifies.

Worked example: moving out on March 10 at $2,000 a month

Now the other direction. Set What's Happening to Moving OUT, the date to March 10, 2026, the rent to 2000, and leave the method on actual days. March also has 31 days, and the count runs from the 1st through the 10th.

Daily rate  = $2,000 ÷ 31 = $64.5161 a day
Days charged = 10 (the 1st through the 10th)
Owed        = $64.5161 × 10 = $645.16

Prorated Rent Owed

$645.16

The supporting lines read "10 days of March 2026 (through move-out on the 10th, both days counted)" and "Daily rate: $64.52 = $2,000 ÷ 31 days (actual days in the month)". If you already paid March in full, $645.16 is what you keep and the balance is what you are owed back.

Under a flat 30-day divisor the same ten days cost $666.67, at $66.67 a day — $21.51 more. Long months are where the flat method costs a tenant money, because it prices a 31-day month as though it were shorter than it is.

Why the daily rate times the days is a few cents off

Multiply the displayed daily rate by the day count and you will not always land on the displayed total. $48.39 × 12 is $580.68, while the July example shows $580.65. In March, $64.52 × 10 is $645.20 against a shown $645.16. Nothing is broken: the total comes from the unrounded rate — $48.3871 and $64.5161 — and only the final figure is rounded.

Official worksheets are not immune. The Caltrans instruction sheet tells its own staff not to round the daily rate at that step, and then its worked examples round anyway: $500 ÷ 30 shown as $16.67, multiplied by 15 days, gives $250.05 where the unrounded arithmetic gives exactly $250.00. On a tenancy vacated February 27 the same habit turns a $50.00 refund into $49.91.

A gap of a few cents cannot have come from the day count or the divisor, because either of those moves the total by dollars. So when a landlord's figure differs from yours by pennies, the thing to settle is which of you rounded first, not the calendar.

Prorated Rent Chart: Daily Rates and Amounts Owed

Three reference tables. The first prices a single day at each month length; the other two price a whole partial month from either end, using the actual-days divisor.

Daily rate by rent and month length

The same rent buys four different daily prices depending on which month you move in:

The flat 30-day method has no separate column because it is the 30-day column, every month of the year. That is the whole design of it: one price per day, from January to December, at the cost of the divisor no longer matching the calendar.

Move-in: what you owe from your date to month end

A $1,500 monthly rent, actual-days divisor, counting the move-in date itself:

Notice how much the month length changes the day count rather than just the price. Moving in on the 25th leaves seven days to pay for in a 31-day month and four in February, which is why a date that feels late in one month is barely late in another.

Move-out: the 1st through your last day

An $1,800 monthly rent, actual-days divisor, counting the move-out date itself. Here the day count is the date, so it is identical across the three columns and only the price per day moves:

Ten days of February cost $642.86 against $580.65 for ten days of July — $62.21 more for the same span of time, because actual-days proration spreads the rent over fewer days and makes each one dearer. For a fixed number of days, a long month is the cheaper one to leave in.

Actual Days or a Flat 30-Day Month?

This is the input that decides the answer, and the one worth opening the lease for. Actual days tracks the calendar; a flat 30 treats every month as the same length, which is convenient for an accounting system and awkward for anyone checking the figure against a calendar.

The same move-in under both methods

Moving in on the 15th, $1,500 a month, in each of the four month lengths:

The two methods agree exactly in a 30-day month and nowhere else. February costs the tenant $50.00 more under actual days on these numbers, or $25.86 more in a leap year; a 31-day month costs $27.42 more under the flat divisor. Those gaps are computed from the unrounded amounts, so they match a subtraction of the two figures above.

Which method favors which side

There is no method that is generally cheaper for tenants. Which one wins depends only on the length of the month you are moving in or out of, because that is the only thing that changes the daily rate. In months of 31 days the actual-days rate is lower, so actual days favors the tenant. In February it is higher, so the flat divisor does. In 30-day months the question is moot.

Push the flat divisor across a whole month and the distortion is easy to see. Occupy every day of a 31-day month on a $1,500 rent and the flat method bills $1550.00 — fifty dollars above the rent it is meant to be dividing, or 3.33% over. Occupy all 28 days of a February and it bills $1400.00, which is 6.67% under. The flat month is a fixed price per day that quietly refuses to add up to the monthly rent.

Direction does not change any of this. Moving in and moving out use the same daily rate; the only difference is which end of the month the days are counted from.

A third convention: an annual rate over 365 days

Some leases, especially commercial ones and long residential terms, prorate on an annual rate: multiply the monthly rent by 12, divide by 365, and charge that per day. The Proration Method control here offers actual days and a flat 30 only, so this one has to be done by hand — but the day count is identical, and only the rate changes.

On a $1,500 rent the annual figure is $18,000, which is $49.3151 a day. Twelve days of July then come to $591.78, sitting between the $580.65 that actual days produces and the $600.00 the flat divisor produces. The 365-day method is the steadiest of the three across a full year, because it is the only one whose daily rate is the same in February as in July and still totals the annual rent.

This is also a good place to see the rounding rule bite. Round the daily rate to $49.32 before multiplying and twelve days come to $591.84, six cents adrift of the correct $591.78. Divide, multiply, then round.

What the rules actually say

Minnesota legislates the question outright. Minnesota Statutes section 504B.116, titled Prorated Rent Required, says that when a lease term ends before the last day of the final month, the rent for that month must be prorated at the average daily rate so the tenant pays only for the days occupancy is allowed — calculated, in the statute's own words, using the actual number of calendar days for the calendar month in which the lease expires. It applies even where the last month was prepaid, and any attempt to waive it by contract is void.

California's Department of Transportation goes the other way for the tenancies it administers, instructing that all prorations of rent and utilities be based on a 30-day month to determine a daily rate, regardless of the number of days in the month. Both are real, current, official positions; they simply serve different purposes, one protecting a departing tenant and one standardizing an agency's books.

Most tenancies are governed by neither. There is no general federal rule setting a divisor for a private lease, and California Civil Code section 1947 — the provision that governs when rent is payable — says only that rent falls due at the end of each period unless the agreement says otherwise. It names no daily rate and no divisor at all, which is exactly why the lease document is the thing to read.

The one federal proration rule in this area covers military moves. Under the Servicemembers Civil Relief Act, a servicemember who terminates a residential lease under orders has any rent paid in advance for a period after the termination date refunded within 30 days. For a lease with monthly rent the termination date is counted in days — 30 days after the next rental payment falls due — so it need not land on the 1st: 30 days after a February 1 due date is March 3 in a 28-day February, and most of a prepaid March comes back.

How to Read Your Result

The readout is designed to be argued with. Every number that went into the total is shown separately, so a disagreement can be traced to a divisor, a day count, or a rounding step rather than left as two totals that differ.

The four lines the panel prints

The large figure at the top is the amount owed for the partial month, printed with two decimals and no thousands separator — a whole month at $1,500 reads as $1500.00.

The line below it names the month and the day count and states which days were included, in the form "12 days of July 2026 (move-in on the 20th, through month end, both days counted)". If that day count is not the one you expected, the disagreement is about the calendar and not about money.

The third line shows the working and splits across the row at the equals sign: "Daily rate: $48.39" on the left, "$1,500 ÷ 31 days (actual days in the month)" on the right. The divisor printed there is the fastest way to confirm the tool used the method you meant to select.

The last line is a standing reminder that the lease may name the proration method and whether move-in day is charged. It appears on every result because it is true of every result.

Checking the figure against what you were quoted

When your number and the leasing office's number differ, three things explain almost all of it. Compare the divisor first — a 31 against a 30 moves a $1,500 half-month by around $27. Then compare the day count, where the question is whether the move date itself was charged. Only then look at rounding, which can account for cents but never for dollars.

Put the agreed figure in writing before the keys change hands. The breakdown lines here are short enough to paste into an email, and a landlord who used a different divisor will usually say so plainly once the question is specific rather than general.

Checking whether the full rent works against what actually reaches your account each month? Convert your pay with the Salary Calculator.

What the form does with a blank or a zero

Both selects arrive pre-set — Moving IN and Actual days in month — and the move date arrives pre-filled, so the only box that starts empty is the rent. That is why the panel opens on a dash instead of an example: the calculation runs when you press Calculate, and it does not re-run as you type.

Press Calculate with the rent box empty and the form stops before the formula and names the field that is missing, as "Enter a value for Monthly Rent." Clear more than one field and the message lists them together instead.

A zero or a negative rent is a different case. Those reach the formula, which refuses them and returns its own message, "Enter the monthly rent", in the amber notice. There is no minimum attribute on the box, so a very large or fractional rent is accepted and calculated as given — $1,495.50 a month is a perfectly valid input.

Limits: When This Does Not Apply

This tool prices one partial calendar month against a month boundary. Several common situations sit outside that, and one of them can produce a figure you should not pay.

One month at a time

The move-in mode always runs to the end of the month and the move-out mode always starts on the 1st, so an arbitrary span — the 10th to the 20th of the same month, say, or a stay that crosses from one month into the next — is not something either mode can express. The daily-rate line gives you what you need for those by hand: take the rate the panel shows, multiply by the days you want, and round at the end. A tenancy running from mid-July to mid-September is one prorated July, a full August, and one prorated September.

The flat 30-day method has no ceiling here

Choose the flat divisor and price a full 31-day month and the answer comes out above the rent: a move-out dated the last day of a 31-day month on a $1,500 rent returns $1550.00. The Caltrans schedule anticipates this and caps it — prorated rent for a partial month cannot exceed the monthly rent, it says, so its own $500.10 example is written down to $500. This calculator applies no such cap, because the cap is a policy rather than arithmetic. Treat any result above one month's rent as one month's rent, and check why the tenancy was being prorated at all.

Whether you get proration at all is a notice question

A prorated final month assumes the tenancy is allowed to end mid-month, and often it is not. New York's Real Property Law section 232-b lets a monthly tenant outside New York City end the tenancy by notifying the landlord at least one month before the expiration of the term — which ends the tenancy on a term boundary, leaving a full final month rather than a partial one. California Civil Code section 1946.1 counts differently: a landlord gives at least 30 days' notice, or 60 days where the tenant has been in place a year or more, measured to a proposed termination date that need not be the end of a rent period. Sort out the end date under your own state's rule first; the proration follows from it.

What the tool does not include

It prices base rent and nothing else. Security deposits, application and admin fees, pet rent, parking, storage, utilities, late charges and any move-in concession all sit outside the calculation, and each is governed by its own clause. It also has no knowledge of where you live: rent-stabilized units, subsidized tenancies and local ordinances can each impose their own method, and a lease that names a method overrides every convention on this page.

Working out what monthly rent your income can carry before you sign anything? Run the numbers through the Home Affordability Calculator.