What Is Pro-Rata Rent?

Pro-rata rent comes up every time a tenant moves in on a date that is not the first of the month. And let's be honest, that is most of the time. Units become available mid-month. Tenants need to start their lease on the 15th because that is when their old lease ends.

The math is straightforward, but a surprising number of landlords either get it wrong or skip it entirely and just charge a full month. Both are bad moves.

How Pro-Rata Rent Works

Pro-rata means "in proportion." When a tenant moves in on the 15th of a 30-day month, they are occupying the unit for 16 days (the 15th through the 30th). They should pay for 16 days, not the full 30.

The formula is simple:

Monthly Rent ÷ Days in Month × Days Occupied = Pro-Rata Rent

For a $1,500/month rent with a move-in date of the 15th in a 30-day month:
$1,500 ÷ 30 = $50 per day
$50 × 16 days = $800 pro-rata rent

The tenant pays $800 for the partial month, then $1,500 for each full month after that. Their regular rent payments start on the 1st of the following month.

When You Need to Calculate Pro-Rata Rent

There are three common scenarios:

Mid-month move-in. The most common. A tenant signs a lease agreement starting on the 10th or 15th. You charge pro-rata rent for the remainder of that month.

Mid-month move-out. If a tenant's lease ends on the 15th or they give notice to vacate mid-month under a month-to-month arrangement, you only charge for the days they occupied the unit.

Lease start date alignment. Some landlords use pro-rata rent to shift a tenant's payment due date to the 1st of the month. The tenant pays a prorated amount for the first partial month, then all future payments are due on the 1st. This keeps your rent roll clean and all tenants on the same payment cycle.

Real Example: Move-In on March 20

Tenant signs a lease starting March 20. Monthly rent is $1,350. March has 31 days.

Daily rate: $1,350 ÷ 31 = $43.55 per day
Days in March from the 20th through the 31st: 12 days
Pro-rata rent: $43.55 × 12 = $522.58

Before move-in, you collect:

• Pro-rata rent for March 20-31: $522.58
• Security deposit: $1,350
• First full month's rent (April): $1,350
• Total due at move-in: $3,222.58

This gets the tenant moved in, secures your deposit, and ensures April rent is already paid. Their next payment of $1,350 is due May 1st.

Calendar Days vs. Standard 30-Day Month

There are two approaches and landlords argue about both:

Actual calendar days. You use the real number of days in the specific month. February has 28 (or 29), June has 30, July has 31. This is the most accurate and legally defensible method.

Standard 30-day month. You assume every month has 30 days regardless of the actual calendar. This simplifies the math but can create small discrepancies. A tenant moving into a February unit using a 30-day calculation pays slightly less per day than they should.

I recommend using actual calendar days. The math difference is small ($1-5 per month in most cases), but actual days are more accurate and hold up better if a tenant ever challenges the calculation.

Common Mistakes With Pro-Rata Rent

Charging a full month for a partial month. If a tenant moves in on the 25th and you charge a full month of rent, you are overcharging them. This is not only unfair, it may violate your landlord-tenant law depending on your state.

Rounding incorrectly. When the daily rate comes out to something like $43.548, round to the nearest cent ($43.55). Do not round the daily rate up to $44 and then multiply. That compounds the rounding error across multiple days.

Not including it in the lease. Your lease should state the pro-rata amount, the period it covers, and when the first full rent payment is due. "Tenant shall pay pro-rata rent of $522.58 for the period March 20-31, 2026. Regular monthly rent of $1,350 is due on the 1st of each month beginning April 1, 2026."

Forgetting move-out pro-rata. If a lease ends on the 15th, the tenant should only pay for 15 days of that month. Charging a full month when the lease clearly ends mid-month will get you in trouble.

How to Handle Pro-Rata Rent in Your Tracking

Pro-rata payments can mess up your rent payment tracking if you are not careful. Your spreadsheet will show a payment that does not match the regular rent amount, and if you are doing any automated calculations, it will throw off your totals.

The cleanest approach: add a "Notes" column to your rent tracker. For the first month, enter the pro-rata amount and note "Pro-rata: 3/20-3/31." Starting the next month, the regular amount shows up and everything lines up.

Frequently Asked Questions

How do you calculate pro-rata rent?

Divide the monthly rent by the number of days in the month to get the daily rate. Multiply by the number of days the tenant will occupy the unit. For $1,500 rent in a 30-day month with move-in on the 20th: $1,500 ÷ 30 = $50/day × 11 days = $550.

Do I use calendar days or a standard 30-day month?

Use actual calendar days for the specific month. It is more accurate and legally defensible. February has 28 days, March has 31. The math difference is small but accuracy matters.

When do I collect pro-rata rent?

Collect it before the tenant moves in, along with the security deposit and first full month's rent. This ensures you are paid for every day the tenant occupies the unit from day one.