$300 000 Mortgage 15 Year Calculator

This calculator helps you determine your monthly mortgage payments for a $300,000 loan over 15 years. Simply enter your interest rate and see how much you'll pay each month, the total interest paid, and your amortization schedule.

How to Use This Calculator

Using this mortgage calculator is simple:

Enter the loan amount ($300,000 by default)
Enter the loan term in years (15 by default)
Enter your annual interest rate (current average is around 6%)
Click "Calculate" to see your monthly payment and other details
Review the results and amortization schedule

The calculator will show you:

Your monthly payment amount
Total amount paid over the loan term
Total interest paid
Amortization schedule chart

Formula Used

The calculator uses the standard mortgage payment formula:

Mortgage Payment Formula

Monthly Payment = P × [r(1 + r)ⁿ] / [(1 + r)ⁿ - 1]

Where:

P = Principal loan amount ($300,000)
r = Monthly interest rate (annual rate ÷ 12 ÷ 100)
n = Number of payments (loan term in years × 12)

This formula calculates the fixed monthly payment for a loan with a fixed interest rate.

Worked Example

Let's calculate a $300,000 mortgage at 6% interest over 15 years:

Principal (P) = $300,000
Annual interest rate = 6% → Monthly rate (r) = 6% ÷ 12 ÷ 100 = 0.005
Loan term = 15 years → Number of payments (n) = 15 × 12 = 180

Plugging into the formula:

Calculation Steps

Monthly Payment = $300,000 × [0.005(1 + 0.005)¹⁸⁰] / [(1 + 0.005)¹⁸⁰ - 1]

First calculate (1 + r)ⁿ = (1.005)¹⁸⁰ ≈ 4.425

Then calculate numerator: 0.005 × 4.425 ≈ 0.022125

Then calculate denominator: 4.425 - 1 = 3.425

Finally: $300,000 × (0.022125 / 3.425) ≈ $2,079.46

So your monthly payment would be approximately $2,079.46.

Frequently Asked Questions

What is the difference between fixed and variable rate mortgages?

A fixed-rate mortgage has the same interest rate for the entire loan term, while a variable-rate mortgage has an interest rate that can change over time. Fixed-rate mortgages provide more predictable payments but may have higher initial rates, while variable-rate mortgages can offer lower initial rates but may have payments that fluctuate.

How much can I afford on a $300,000 mortgage?

Your ability to afford a $300,000 mortgage depends on your income, debts, and credit score. A general rule is that your housing payment (including mortgage, property taxes, insurance, and PMI if applicable) should not exceed 28% of your gross monthly income, and your total debt payments should not exceed 36% of your income.

What are closing costs for a $300,000 mortgage?

Closing costs for a $300,000 mortgage typically range from 2% to 5% of the loan amount, or $6,000 to $15,000. These costs include fees for appraisal, title search, insurance, origination, and other services. Some costs are paid at closing while others are paid throughout the loan process.