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Free Mortgage Calculator Online
Estimate mortgage principal and interest payments, monthly housing costs, total interest and payoff changes from extra payments.
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At a glance
Mortgage Calculator — Estimate mortgage principal and interest payments, monthly housing costs, total interest and payoff changes from extra payments.
Free for the core workflow, no account required. The calculation is performed locally in the browser from the values you enter.
About Mortgage Calculator
Estimate mortgage principal and interest payments, monthly housing costs, total interest and payoff changes from extra payments.
The mortgage calculator separates principal-and-interest payment from optional monthly property tax and insurance estimates. It also shows how extra monthly payments can change the modeled payoff timeline. The true monthly cost of a home is PITI: Principal + Interest + Taxes + Insurance — plus often HOA fees. Calculators showing only P&I understate reality by 25–40% in many markets, which is why this one includes the extras. Worked example — a $400,000 loan at 6.5% for 30 years. The monthly rate is 0.065 ÷ 12 = 0.0054167 and the term is 360 months. The factor (1.0054167)^360 ≈ 6.991, so the principal-and-interest payment is 400,000 × 0.0054167 × 6.991 ÷ 5.991 ≈ $2,528 a month. Total paid is 2,528 × 360 = $910,080, of which $510,080 is interest. But that is not the monthly cheque: add property tax of $450 and homeowner’s insurance of $180 and the real payment is $3,158 — 25% higher than principal and interest alone. Table — the same $400,000 at other terms and rates: 15 years at 6% gives about $3,376 a month and $207,590 total interest; 20 years at 6.25% gives about $2,924 and $301,808; 30 years at 6.5% gives $2,528 and $510,080; 30 years at 7% gives about $2,661 and $558,032. A single percentage point on the 30-year loan costs about $133 a month, or nearly $48,000 over the life of the loan. Before / after — before: budgeting $2,528 a month because that is the number the headline calculator showed; after: $3,158 including tax and insurance, with the 15-year alternative priced alongside it. The down payment changes everything else too: putting down 20% avoids private mortgage insurance, which commonly adds 0.5–1% of the loan amount per year — on $400,000 that is $167–$333 a month until the loan-to-value ratio drops. And an extra $200 a month on the 30-year example, applied to principal, removes roughly 6 years and about $116,000 of interest. Sources: Consumer Financial Protection Bureau, “Buying a House” (accessed November 2026); Freddie Mac, “Primary Mortgage Market Survey” (accessed November 2026). Content last reviewed: November 2026.
Primary objective: Models mortgage principal-and-interest payments with optional monthly tax, insurance and extra-payment scenarios.
Privacy assurance: The calculation is performed locally in the browser from the values you enter.
How to Use Mortgage Calculator
- Enter the loan amount, interest rate and mortgage term.
- Add optional monthly tax and insurance estimates.
- Review the payment, housing estimate, interest and amortization checkpoints.
- Enter the loan amount after the down payment, not the house price — the loan is what you pay interest on.
- Add monthly property tax and insurance estimates to get the real payment, not just principal and interest.
- Compare 15-year and 30-year terms on the same loan to see the interest saving against the higher payment.
- Add an extra monthly payment to see how many years and dollars it removes.
- Check the 28/36 rule: housing under 28% of gross monthly income, all debts under 36%.
Key Use Cases & Applications
- home-buying planning
- mortgage scenario comparison
- understanding amortization
- Getting the real monthly number before making an offer on a house.
- Comparing the lifetime cost of 15-year vs 30-year terms.
- Getting the real monthly number, including tax and insurance, before making an offer on a house.
- Comparing the lifetime cost of 15-year versus 30-year terms on the same loan.
- Checking whether a 1% rate rise keeps the payment inside the 28% affordability rule.
Frequently Asked Questions
Does the mortgage calculator include taxes and insurance?
Optional monthly estimates can be added to the principal-and-interest payment.
Can I model extra payments?
Yes. Add an extra monthly payment to see the modeled payoff and interest effect.
Is this a lender quote?
No. It is a mathematical estimate and does not include every lender fee, escrow rule or local charge.
Why is my actual payment higher than principal + interest?
Property tax and homeowner's insurance are usually escrowed into the monthly payment. Add HOA fees and possible PMI (if down payment < 20%) for the full picture.
How much house can I actually afford?
The common rule is housing costs under 28% of gross monthly income, total debt under 36%. Run the numbers conservatively — the maximum approved loan is rarely the comfortable loan.
Is a 15-year mortgage always better than 30-year?
It saves massive interest and builds equity faster, but the higher payment reduces flexibility. Many buyers take the 30-year and make extra payments voluntarily.
What is the monthly payment on a $400,000 mortgage at 6.5% for 30 years?
About $2,528 for principal and interest. With $450 tax and $180 insurance, the real monthly cost is about $3,158.
How much does a 1% rate rise cost?
On the $400,000, 30-year loan, moving from 6.5% to 7% raises the payment from about $2,528 to $2,661 — roughly $48,000 over the loan.
What does a 20% down payment save me?
It usually avoids private mortgage insurance, which commonly costs 0.5–1% of the loan per year — $167–$333 a month on a $400,000 loan.
Is a 15-year mortgage worth the higher payment?
It saves about $302,000 of interest on the example loan versus 30 years, but the payment is about $848 higher, so it only works if the budget survives it.
What does an extra $200 a month do?
Applied to principal on the 30-year example, it removes roughly 6 years from the term and about $116,000 of interest.
Why is my actual payment higher than the calculator’s principal and interest?
Property tax and insurance are usually escrowed into the payment, and a down payment under 20% adds PMI. Together they commonly add 25–40% to the P&I figure.