Prorated Rent and Partial-Month Pay: 30-Day vs. Actual-Day Methods
October 29, 2026
When a tenant moves in or out mid-month, or an employee starts or leaves part-way through a pay period, the amount owed is prorated: a fraction of the full amount based on the days covered. There is more than one accepted way to calculate the fraction, and they give slightly different answers, so check the lease or contract for the method.
For $1,800 monthly rent and a move-in on the 12th of a 30-day month, the tenant occupies 19 days (the 12th to the 30th inclusive). Method 1, the actual days in the month: $1,800 ÷ 30 × 19 = $1,140. In a 31-day month with a move-in on the 12th, the occupancy is 20 days: $1,800 ÷ 31 × 20 = $1,161.29.
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Open the Date Calculator →Three Common Methods
Actual days in the month: daily rate = monthly rent ÷ days in that month. It results in higher daily rates in short months (February: $1,800 ÷ 28 = $64.29) and lower in long ones ($58.06 in a 31-day month). Fixed 30-day month: daily rate = monthly rent ÷ 30 regardless of the month, which simplifies accounting. Annual method: daily rate = (monthly rent × 12) ÷ 365 = $59.18 for $1,800, so the 19 days cost $1,124.38. All methods are legitimate; the annual method is the most consistent across months, and the 30-day method is the simplest.
Some leases specify prorating from the move-in date to the end of the month, with the next full month charged in full.
| Method | Daily rate on $1,800 rent | Cost for 19 days |
|---|---|---|
| Actual days (30-day month) | $60.00 | $1,140.00 |
| Fixed 30-day month | $60.00 | $1,140.00 |
| Annual (365 days) | $59.18 | $1,124.38 |
| Actual days (31-day month, 20 days) | $58.06 | $1,161.29 |
| Actual days (28-day month, 10 days) | $64.29 | $642.86 |
Partial-Month Salary
For an employee who starts mid-month, employers often use working days: monthly salary ÷ working days in the month × days worked. A $5,200 monthly salary in a month with 22 working days gives $236.36 a day; starting on the 12th, with 14 working days left, earns $3,309.09. Another common approach is the calendar-day method: $5,200 ÷ 30 × 19 = $3,293.33. Or an annual method: annual salary ÷ 260 working days = $240 a day (for $62,400). Differences are modest, but they matter to payroll accuracy. The method should be stated in the employment contract or payroll policy.
Move-Out, Deposits, and Utilities
If the lease ends mid-month, the tenant typically pays rent through the last day of occupancy, but laws and leases vary: some require notice by a certain date and a full month's rent regardless. Security deposits are returned within periods set by local law, minus legitimate deductions. Utilities are prorated by meter readings or days of use. When splitting costs with a roommate who leaves mid-cycle, prorate bills by days present.
Tips
Ask your landlord how proration will be calculated before signing. Get the amount in writing, including the due date of the partial payment. Use a date calculator to count days exactly, and note whether move-in and move-out days are both included. For a start date in the middle of a pay period, ask your payroll department. A difference of a few dollars is normal; large differences deserve a question.
Frequently Asked Questions
How do you prorate rent?
Divide monthly rent by the days in the month (or 30, or use an annual rate) and multiply by the days occupied.
Which proration method is correct?
All are used. The lease or contract should specify one.
Is the move-in day counted?
Usually yes, and it should be spelled out in the lease.
How do I prorate a salary?
Multiply a daily rate based on working days, calendar days, or the annual rate by days worked.
How much is rent per day on $1,800 a month?
About $59 to $64 depending on the method and month.