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Mortgage Calculator

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Monthly payments, total interest and a full amortization schedule for any home loan.

Free to use · No account needed

Payback mode
Amortization schedule (by year)
Year Payment Interest Principal Balance

Principal and interest only. Property tax, insurance and PMI are not included. * In equal principal mode, the monthly payment decreases each month as the outstanding balance shrinks.

How to use

  1. Enter the loan amount, annual interest rate and term in years.
  2. Choose a payback mode - Equal total payment (standard mortgage, fixed monthly bill) or Equal principal paydown (monthly payment decreases, less total interest).
  3. Optionally add an extra monthly payment to see how much faster you pay off the loan.
  4. Monthly payment, total interest and the full year-by-year amortization table update instantly.

Estimate monthly mortgage payments from loan amount, interest rate and term. See principal vs interest breakdown, total interest paid and what rate changes mean over 15 vs 30 years. A first-pass planning tool for home buyers.

Use cases

1. Use case: Compare loan options Check a 30-year vs 15-year mortgage, or compare equal-payment vs equal-principal paydown to see total interest.

2. Use case: Plan extra payments Add an extra monthly payment and see how many years you can cut off the loan and how much interest you save.

Practical tips

The monthly figure combines principal and interest only — property tax, insurance and fees are not included, so budget above the displayed number. Amortization means early payments are mostly interest; the principal-to-interest split shifts over the term, and the schedule shows it. Extra principal payments cut total interest far more than the same amount spread over the term — model a round number to see the effect. Compare terms on total cost, not just the monthly payment. Like every tool on this site, the Mortgage Calculator runs entirely in your browser: the data you enter never leaves your device, nothing is uploaded to a server, and the tool keeps working if your connection drops.

Common mistakes

The monthly number is the beginning of the analysis, not the end:

  • Budgeting to the displayed monthly figure — it is principal and interest only; tax, insurance and fees sit on top.
  • Comparing loan terms by monthly payment instead of total cost: longer terms are cheaper monthly and far more expensive overall.
  • Ignoring amortization — early payments are mostly interest, which is why extra principal early saves the most.
  • Comparing rate quotes that include discount points against quotes that do not; compare on the same basis.

Frequently asked questions

Does the Mortgage Calculator send my data anywhere?

No. It runs entirely in your browser — your input is processed on your device and never uploaded. Refresh the page and it still works offline.

How do extra principal payments affect the loan?
They cut total interest far more than spreading the same amount over the term, because interest is charged on the remaining balance. Model a round extra amount per month and watch the payoff date and total interest in the schedule — the early years benefit most.
What is amortization, in plain terms?
Each payment covers that month's interest first, with the rest reducing the balance. As the balance falls, the interest share shrinks and more of the same payment goes to principal. The schedule shows this split for every payment over the term.
How is the monthly payment calculated?
It uses the standard amortization formula M = P × r × (1+r)^n / ((1+r)^n - 1), where P is the loan amount, r the monthly rate (annual / 12), and n the number of payments (years × 12). In Equal principal paydown mode, each month pays the same principal (P/n) plus the interest on the remaining balance.
What's the difference between equal total payment and equal principal paydown?
Equal total payment (the standard) keeps your monthly bill the same for the whole loan - early payments are mostly interest, later ones are mostly principal. Equal principal paydown keeps the principal portion fixed and the interest portion shrinks as the balance shrinks, so monthly payments decrease over time. Equal principal saves total interest and pays off the loan slightly faster.
Why is my total interest so high?
Interest compounds on the remaining balance, so early payments are mostly interest. A 30-year loan at 6% pays roughly as much in interest as the loan itself. Lowering the rate or term cuts total interest significantly - or switch to equal principal paydown.
Should I include property tax and insurance?
This calculator covers principal and interest only. Property tax, insurance and PMI are added by lenders separately and vary by location.

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