Exact Days in Month (Most Accurate)
Banker's Month (30 Days)
Total Days in Month:0
Days Occupied:0
Daily Rate:$0.00
Prorated Rent:$0.00
function calculateProratedRent() {
// Get Inputs
var rentInput = document.getElementById('prMonthlyRent').value;
var dateInput = document.getElementById('prMoveInDate').value;
var method = document.getElementById('prCalcMethod').value;
var errorDiv = document.getElementById('prErrorMessage');
var resultBox = document.getElementById('prResultBox');
// Reset display
errorDiv.style.display = 'none';
resultBox.style.display = 'none';
// Validation
if (!rentInput || isNaN(rentInput) || rentInput daysInMonth) {
// Edge case: Move in on 31st in a 30-day calculation method
daysOccupied = 0;
} else {
daysOccupied = daysInMonth – day + 1;
}
// Calculation
var dailyRate = rent / daysInMonth;
var totalProrated = dailyRate * daysOccupied;
// Display Results
document.getElementById('prTotalDays').innerText = daysInMonth;
document.getElementById('prOccupiedDays').innerText = daysOccupied;
document.getElementById('prDailyRate').innerText = "$" + dailyRate.toFixed(2);
document.getElementById('prFinalAmount').innerText = "$" + totalProrated.toFixed(2);
resultBox.style.display = 'block';
}
What is Prorated Rent and Why Does it Matter?
Moving into a new apartment rarely aligns perfectly with the first day of the month. When you move in on the 12th, 15th, or 25th, you shouldn't be expected to pay for the days the unit sat empty. This is where prorated rent comes in.
Prorated rent is a calculated portion of the monthly rental rate that corresponds to the number of days you actually occupy the property during a partial month. It ensures fairness for both the tenant (who doesn't pay for unused time) and the landlord (who gets paid for every day the unit is occupied).
How to Calculate Prorated Rent
While our calculator above handles the math instantly, understanding the formula is helpful for lease negotiations. There are two primary methods used by property managers:
Method 1: The Exact Days Method (Most Common)
This method is generally considered the fairest because it accounts for the specific number of days in the move-in month (28, 29, 30, or 31).
Determine the Daily Rate: Divide the monthly rent by the total number of days in that specific month.
Calculate Occupied Days: Subtract your move-in day from the total days in the month, then add 1 (to include the move-in day itself).
Multiply: Daily Rate × Occupied Days = Prorated Rent.
Example: Moving in on September 15th with $1,500 rent.
$1,500 ÷ 30 days = $50/day.
30 – 15 + 1 = 16 days occupied.
$50 × 16 = $800.
Method 2: The Banker's Month (30-Day Standard)
Some leases stipulate a "Banker's Month" calculation, which assumes every month has 30 days, regardless of the calendar. This simplifies accounting but can slightly favor the landlord in 31-day months or the tenant in February.
Example: Moving in on August 15th (31 days actual) using Banker's logic ($1,500 rent).
$1,500 ÷ 30 = $50/day.
30 – 15 + 1 = 16 days occupied.
Total: $800 (vs $822.58 if using the exact 31-day method).
When is Rent Prorated?
Proration typically occurs in two scenarios:
Move-in: When your lease starts on any day other than the 1st of the month.
Move-out: If you agree to vacate the property mid-month (though many leases require full month payment upon termination, so check your agreement).
Frequently Asked Questions
Does proration include the move-in day?
Yes. You are technically occupying the unit on the day you receive the keys, so you are charged for that day.
When is prorated rent due?
Policies vary. Some landlords require the prorated amount upfront before move-in. Others require the full first month's rent upfront and apply the prorated amount to the second month of the lease.