Calculate exactly how much rent you owe for a partial month when moving in or out mid-cycle. Compare calendar day and 30-day banking methods with detailed breakdowns of daily rates, days occupied, and total prorated amounts. Whether you're a tenant moving in mid-month or a landlord preparing a lease amendment, this tool gives you accurate, instant prorated rent calculations.
Enter your monthly rent, move-in and move-out dates, and choose a proration method. The calculator will show you the exact prorated amount plus a comparison of both common methods side by side.
Prorated rent is the portion of full monthly rent a tenant pays when they occupy a rental unit for only part of a month — typically due to a mid-month move-in or move-out. The formula adjusts the monthly obligation to reflect the actual days the tenant has possession of the property.
The calculation depends on which method your lease specifies. Here is the exact formula for each:
Important distinction: For mid-month move-outs, the same formulas apply but you use the month you're vacating to determine the number of days. If your move-in was in January but you're moving out in March, the March month length determines the daily rate (under the calendar method). For the 30-day method, it's always 30 regardless.
Example: A tenant moves in on March 15th with a monthly rent of $2,000.
Calendar Days Method: March has 31 days. Days occupied = 17 (Mar 15–31). Daily rate = $2,000 ÷ 31 = $64.52. Prorated rent = $64.52 × 17 = $1,096.77
30-Day Banking Method: Daily rate = $2,000 ÷ 30 = $66.67. Prorated rent = $66.67 × 17 = $1,133.33
The calendar method results in a lower payment because March has 31 days (more days to spread the rent across).
Second example — move-out: A tenant vacates on February 20th with a monthly rent of $1,500. February has 28 days. Days occupied = 20.
Calendar Days: $1,500 ÷ 28 = $53.57/day. $53.57 × 20 = $1,071.43
30-Day Banking: $1,500 ÷ 30 = $50.00/day. $50.00 × 20 = $1,000.00
Here the banking method saves $71.43 because it ignores February's shorter month. This illustrates why tenants moving in February should check their lease method carefully.
When you move into (or out of) a rental property in the middle of the month, you shouldn't have to pay a full month's rent for days you don't occupy the unit. Prorated rent splits the monthly rent into daily increments, charging you only for the days you actually have possession. This is standard practice across the residential rental industry and protects both tenants and landlords from unfair charges or lost revenue.
According to data from the U.S. Census Bureau and rental market tracking firms, roughly one in three lease signings in the United States involves a start date outside the 1st of the month — making prorated rent a near-universal experience for renters. With median monthly rents in major cities ranging from $1,200 (Atlanta) to $3,800 (San Francisco), even small differences in proration methods can translate to meaningful dollar amounts of $50–$200 or more per transaction.
The core concept is simple: the monthly rent covers one full calendar month. If you occupy the unit for only a portion of that month, you pay a proportional share. The two methods for determining that share differ in how they define "a month." This calculator is designed for tenants, landlords, property managers, and real estate professionals who need quick, accurate prorated rent figures without manual math errors.
This is the standard method used by most residential landlords. It divides the monthly rent by the actual number of days in that specific month:
Because February has fewer days than March, the daily rate is higher in February — meaning prorating in February actually costs more per day than in a 31-day month.
Some leases — especially commercial and corporate housing agreements — specify a flat 30-day month for prorating purposes. This means the daily rate is always the same (rent ÷ 30), regardless of whether the actual month has 28 or 31 days. This simplifies budgeting but can be slightly more expensive for tenants moving into long months (31 days) and slightly cheaper for short months (28 days).
The term "banking method" comes from the financial industry, where many interest calculations and loan amortizations use a 30/360 day count convention. Landlords who use this method often do so for consistency — every month has the same daily rate, making it easier to calculate partial-month charges across lease terms that span multiple months or years.
One practical implication: if you move in on the 15th of a 31-day month like January, the calendar method gives you 17 days of occupancy at a daily rate of rent ÷ 31, while the banking method gives you 17 days at rent ÷ 30. For a $2,000 apartment, that's a $36.56 difference — the banking method costs more. The reverse is true in February (28 days): the banking method saves you money because you pay a lower daily rate than the calendar method would produce.
Always check your lease agreement first. If the lease is silent on proration method, most states default to the calendar days method by custom. When in doubt, ask your landlord or property manager which method they use before signing.
Proration protects both parties. Tenants avoid paying for days they don't live in the unit, and landlords keep their cash flow predictable without leaving units vacant for a full rental cycle. A unit rented on the 15th of the month still earns the landlord rent for the second half of that month, and the tenant gets the keys without waiting for the 1st.
Proration also comes into play at move-out. If you give notice and vacate on the 20th, most leases require you to pay only through your final day of possession (though some leases require a full month's notice regardless of move-out date — check your notice clause carefully). In practice, move-out proration is often handled through the security deposit: the landlord collects full rent upfront and then credits the unused portion back after the tenant vacates.
One thing to keep in mind: prorated rent is almost always calculated in advance for move-ins (you pay on or before your start date), and after the fact for move-outs (deducted from your security deposit or invoiced separately). Make sure you understand which applies to your situation so there are no surprises at the end of your tenancy.
Whether you're a tenant double-checking your landlord's math or a landlord preparing a lease amendment, the process is the same. Here's how to calculate prorated rent in four steps:
Let's say your monthly rent is $1,800 and you move in on September 12th. September has 30 days, so you'll occupy 19 days (Sept 12 through Sept 30).
Interesting note: in any 30-day month, both methods produce the exact same result! The methods only diverge in 31-day months and in February.
Now imagine the same $1,800 rent, but you're moving out on July 10th. July has 31 days, so you occupy 10 days (July 1 through July 10).
The calendar method saves you about $19 here because July's 31 days lower the daily rate. This is exactly why tenants should care which method their lease uses.
Suppose your rent is $2,100 and you move in on February 10th of a standard year. February has 28 days, so you occupy 19 days.
Notice the spread: the banking method is $95 cheaper than the standard-year calendar method because it spreads the rent across 30 days instead of 28. That's a meaningful difference — worth knowing before you sign a February lease.
Prorated rent comes up in several everyday situations. Here are the four most common scenarios and how to handle each:
You sign a lease starting on the 15th. The landlord charges you prorated rent for the 15th through the 31st, then full rent on the 1st of the following month. Make sure your lease states the exact move-in date and the prorated amount in writing — a verbal agreement can lead to disputes later.
Your lease officially starts on the 1st, but the landlord lets you move in a few days early to receive furniture deliveries or set up utilities. Some landlords offer these days free as a goodwill gesture; others charge prorated rent for the early-access days. Clarify this in writing before you take the keys.
You vacate on the 20th instead of the 31st. You owe rent through the 20th only — provided you gave proper notice as required by your lease. Many leases require 30 days' written notice, and if you give notice on the 1st and leave on the 20th, you may still owe rent through the end of your notice period even if you're not living there.
If your lease runs from the 1st to the last day of the month, you simply pay full rent — no proration needed. This is why many landlords prefer month-to-month or 1st-to-1st leases: they avoid proration math entirely and keep accounting simple.
At move-out, landlords often reconcile the security deposit against the final prorated rent. For example, if you prepaid full rent for the month but vacated on the 10th, the landlord should credit the unused days (the 11th through month-end) toward your deposit refund. Keep your payment records so you can verify the math.
When a roommate moves out mid-month and a new one moves in, proration splits the rent between them. A common approach: the departing roommate pays through their last day, the new roommate pays from their first day, and the gap (if any) is covered by the remaining roommate. If both overlap, the landlord or roommates must agree on how to split the overlapping days.
Use this quick-reference table to see how the daily rate changes across different month lengths and rent amounts. The daily rate is the foundation of every proration calculation.
| Monthly Rent | 28-Day Month (Feb) | 29-Day Month (Leap Feb) | 30-Day Month | 31-Day Month | 30-Day Method |
|---|---|---|---|---|---|
| $1,000 | $35.71 | $34.48 | $33.33 | $32.26 | $33.33 |
| $1,500 | $53.57 | $51.72 | $50.00 | $48.39 | $50.00 |
| $2,000 | $71.43 | $68.97 | $66.67 | $64.52 | $66.67 |
| $2,500 | $89.29 | $86.21 | $83.33 | $80.65 | $83.33 |
| $3,000 | $107.14 | $103.45 | $100.00 | $96.77 | $100.00 |
| $3,500 | $125.00 | $120.69 | $116.67 | $112.90 | $116.67 |
| $4,000 | $142.86 | $137.93 | $133.33 | $129.03 | $133.33 |
| $4,500 | $160.71 | $155.17 | $150.00 | $145.16 | $150.00 |
| $5,000 | $178.57 | $172.41 | $166.67 | $161.29 | $166.67 |
Note how the daily rate in the 30-day method column always matches the 30-day-month calendar column — those are mathematically identical. The differences only appear in 28-, 29-, and 31-day months.
| Factor | Calendar Days Method | 30-Day Banking Method |
|---|---|---|
| Days used in formula | Actual month length (28–31) | Always 30 |
| Commonly used in | Residential leases, apartments | Commercial leases, corporate housing |
| Daily rate consistency | Varies month to month | Always the same |
| Cheapest for tenant | 31-day months (lowest daily rate) | 28-day months (vs calendar) |
| Most expensive for tenant | 28-day February (highest daily rate) | 31-day months (vs calendar) |
| Legal standard | Default in most states | Only if lease specifies |
The key takeaway: if you have a choice, the calendar days method is almost always more favorable to tenants in 31-day months, while the banking method can be more favorable in February. Over the course of a year with one prorated month, the difference is usually small — but in expensive markets it can add up to real money.
Prorated rent is not governed by a single federal law — it falls under each state's landlord-tenant statutes. While no state explicitly requires a specific proration formula, many states have general rules that shape how proration works in practice:
Because rules vary so widely, this calculator is a planning tool — not legal advice. For disputes, contact your state's department of consumer affairs, housing authority, or a local tenant rights organization. Many offer free mediation and can review your lease and the landlord's calculations at no cost.
The calendar days method is the most common standard for residential leases in the United States. However, some leases — particularly commercial or corporate housing agreements — specify the 30-day banking method. Always check your lease first. If no method is specified, most states and landlord-tenant practices default to calendar days.
In most states, tenants are only legally obligated to pay rent for the period they actually possess the unit. If you move in mid-month, the landlord is generally required to charge prorated rent rather than a full month. Some states have explicit laws about this, while others rely on common practice. If a landlord demands a full month's rent for a mid-month move-in, you may want to consult your state's tenant rights resources.
Under the calendar days method, February is treated the same as any other month — you divide by the actual number of days. In a standard year, February has 28 days (daily rate = rent ÷ 28). In a leap year, February has 29 days (daily rate = rent ÷ 29). The 30-day banking method simply uses 30 regardless, so February follows the same formula as any month. Leases that use the calendar method often result in a noticeably higher daily rate in February because the rent is spread across fewer days.
If your lease starts on the 1st and ends on the last day of the month, no proration is needed — you owe the full month's rent. Proration only applies when your tenancy begins or ends on a date other than the 1st. Some landlords may still prorate the first month if the lease signing happens after the 1st, but in most cases a standard 1st-of-month start means a full month's payment is due.
Many landlords allow utility proration for mid-month move-ins, especially if utilities are billed through the property (e.g., water, trash, or bundled services). This is typically calculated the same way as rent proration. However, if utilities are in your name and billed directly by the utility company, you'll handle your own start/stop dates and won't need proration. Always ask your landlord about their utility proration policy before moving in.
When one roommate moves out mid-month and a new roommate moves in, you can prorate each person's share based on their occupancy days. For example, if total rent is $2,400 and Roommate A moves out on the 10th of a 30-day month, they owe $2,400 ÷ 2 roommates = $1,200 per person share. Roommate A's prorated share = ($1,200 ÷ 30) × 10 = $400. The new roommate moving in on the 11th owes ($1,200 ÷ 30) × 20 = $800. The remaining roommate pays their full $1,200. This ensures everyone pays only for the days they actually occupy the unit.
If your lease specifies a proration method but your landlord calculates it differently, the lease language controls. Bring the discrepancy to the landlord's attention in writing, pointing to the specific clause in your lease. If the lease doesn't specify a method, the default is typically the calendar days method. If you can't resolve it amicably, your state's tenant rights office, housing authority, or a tenant advocacy group can help mediate. Most landlords will correct the calculation once the lease language is pointed out — many simply use a default method out of habit without realizing the lease says otherwise.
Yes, prorated rent frequently interacts with security deposits — especially at move-out. If you paid full rent for the month but vacated early (say on the 15th), the unused rent (16th through month-end) is typically credited toward your security deposit refund or applied to any outstanding charges. Conversely, if you owe prorated rent for a mid-month move-out and it wasn't collected upfront, the landlord may deduct it from your security deposit. Most states require an itemized list of deductions from the deposit, including prorated rent calculations, returned to you within 14–45 days depending on local law.
⚠️ Important: Prorated rent policies vary by state, lease agreement, and landlord. Always check your lease for the specific proration method used. This calculator provides estimates only and should not be considered legal or financial advice.