Mortgage Calculator
Estimate your monthly mortgage payment, total interest, and full amortization at a glance.
Result
Principal & interest of $2,023/mo on a $320,000 loan over 30 years at 6.5%.
- Loan amount
- $320,000
- Principal & interest
- $2,023
- Tax + insurance
- $525
- Total interest paid
- $408,142
- Total of payments
- $728,142
- Term
- 30 years
Inputs
Try an example
Formula
M = P · r(1+r)ⁿ ÷ ((1+r)ⁿ − 1)
Where P is the loan principal, r is the monthly interest rate (annual ÷ 12), and n is the total number of monthly payments (years × 12).
How it works
Each payment covers interest first; what's left chips away at the principal. Early in the loan most of your payment is interest. Over time the balance falls, so more of every payment goes toward equity.
Common mistakes
- Forgetting taxes, insurance, and HOA — they often add 15–25% to the payment.
- Comparing only monthly payments instead of total interest paid.
- Underestimating closing costs (typically 2–5% of the loan).
- Assuming a fixed rate when the loan is adjustable (ARM).
Source & methodology
Uses the standard fixed-rate amortization formula. Tax and insurance, when provided, are divided evenly across 12 months. Estimates do not include PMI, HOA dues, or origination fees.
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Last updated
The data and formulas powering this calculator were last reviewed on Feb 1, 2025.
Calcxo gives you the answer plus the reasoning behind it.
Quick answer
Mortgage Calculator: in one paragraph
A mortgage payment combines principal (paying down what you borrowed) and interest (the cost of borrowing). The mortgage calculator turns your loan amount, rate, and term into a fixed monthly payment plus a clear breakdown of total interest over the life of the loan.
What this calculator does
Enter the home price, down payment, interest rate, and term. The calculator returns your estimated monthly principal-and-interest payment, total interest over the loan, and a sense of how much you'll have paid by the end.
Why people use it
- Decide what price range is realistic before you tour homes.
- Compare 15-year vs 30-year terms with real dollar numbers.
- See how a 0.5% rate change moves your monthly payment.
- Estimate the total cost — not just the sticker price.
$300,000 loan at 6.5% for 30 years
A concrete walkthrough you can follow line by line.
You borrow $300,000 at a 6.5% fixed rate over 30 years.
1. Convert the rate
6.5% per year ÷ 12 ≈ 0.5417% per month
2. Count the months
30 years × 12 = 360 monthly payments
3. Use the mortgage formula
M = P × r(1+r)^n / ((1+r)^n − 1)
Result
Monthly payment ≈ $1,896. Total interest over 30 years ≈ $382,633.
When to use this calculator
- Pre-shopping for a house, refinance, or rate negotiation.
- Comparing two loan offers side by side.
- Pair with the affordability and DTI calculators for a fuller picture.
Common mistakes
- Forgetting to include property tax, insurance, and HOA in the real monthly cost.
- Comparing APRs and rates without checking points and fees.
- Looking only at monthly payment and ignoring total interest paid.
- Assuming current rates won't move before you lock.
Learn more
Deeper reads from the Calcxo learn library.