Mortgage Calculators

Estimate your monthly mortgage payment — principal and interest, plus optional property tax, home insurance, PMI, and HOA. For a full walkthrough of every field, an amortization breakdown, and the FAQ, see the full Mortgage Calculator page.

Estimate the home price your income and down payment support, using the standard 28/36 debt-to-income guidelines lenders apply. For how the guidelines work and what to watch for, see the full House Affordability Calculator page.

What these calculators compute

MTGCalculator.net is a set of focused mortgage and loan calculators that run entirely in your browser. The two embedded on this page are the ones people reach for first. The Mortgage Payment Calculator turns a home price, down payment, rate, and term into a full monthly payment — principal and interest, plus optional property tax, home insurance, PMI, and HOA — and reports the loan amount, the loan-to-value ratio, and the total interest over the term. The House Affordability Calculator runs the question the other way: from gross income, existing monthly debts, and a down payment, it estimates the largest home price whose monthly housing cost fits the lending guidelines. Both are fully usable here; their dedicated pages, Mortgage Calculator and House Affordability Calculator, carry the long walkthroughs.

Behind the two tools is one tested finance engine, and the wider directory exposes the rest of it: amortization schedules, refinance savings and break-even, fee-adjusted APR, down payments, biweekly payoff, mortgage points, home-equity lines, auto and student and personal and business loans, credit-card and general debt payoff, and debt-to-income ratios. Every result in the examples below is computed when this page is built by the same engine that runs in your browser, from inputs invented for the example and labelled as such. No rate, price, or balance on this page is a market figure or a quote.

The conventions every calculator shares

The methodology page states these conventions once; here is what they mean for the two tools above and the rest of the directory.

• The payment formula. Payments use the standard amortized-loan (PMT) formula with monthly compounding, the convention behind US mortgages and most consumer loans. The annual rate is divided by twelve for a monthly rate, the term is years × 12 payments, and the result is the one fixed payment that retires the balance exactly at the last month. The payment-formula guide derives it step by step.
• The month-by-month schedule. A fixed monthly payment covers the interest accrued on the balance that month, and the remainder reduces the principal; the schedule is computed one month at a time, so extra payments and payoff dates are exact rather than approximate. That is why the total interest is a sum of monthly charges, not the payment multiplied by the term.
• The affordability guideline. Affordability uses the 28/36 debt-to-income guidelines: a housing-cost share of gross monthly income and a total-debt share, with the smaller of the two setting the budget. The property tax that scales with the home price being solved for is handled with a closed-form rearrangement rather than an approximation.
• The rounding policy. Internally, every calculation keeps the full precision of IEEE-754 double-precision arithmetic — nothing is rounded between steps, so a schedule stays accurate across hundreds of payments. On screen, money is rounded to the cent, or to whole dollars for large totals like lifetime interest. Your lender's figure may differ by a few cents depending on their rounding and day-count conventions — the difference is presentational, not an error.

One more shared rule: every engine function validates its inputs before any arithmetic runs and returns either a typed result or an explicit, human-readable error. A non-numeric, negative, or out-of-range value comes back as a sentence explaining the problem, never as a NaN, an infinity, or a wrong number. The interface only formats what the engine returns; it does no arithmetic of its own.

A worked mortgage payment

Take a fictional $360,000 home with $72,000 down — 20% of the price — at 6.25% over 30 years, with an illustrative 1.15% property-tax rate and $1,680 a year of insurance. The loan is $360,000 − $72,000 = $288,000, a loan-to-value ratio of 80%. Principal and interest come to $1,773.27 a month. Property tax is $360,000 × 1.15% ÷ 12 = $345.00, and insurance is $1,680 ÷ 12 = $140.00. Because 20% down leaves the loan-to-value at 80% — not above 80% — the engine adds no PMI line. The full monthly payment is $2,258.27.

The schedule behind that payment is built one month at a time. In month one the balance is the whole $288,000, so interest is $288,000 × (6.25% ÷ 12) = $1,500.00, and only $273.27 of the $1,773.27 principal-and-interest payment reaches principal — 84.6% of that first payment is interest. Across the first year the schedule records $17,904 of interest against $3,375 of principal, leaving $284,625 owing; by year 30 the split has inverted to $703 of interest against $20,576 of principal. Nothing is front-loaded by anyone: the balance is simply large for a long time, and the interest charge follows the balance. Over the full term the loan pays $350,376 in interest, for a total of payments of $638,376 — the loan amount plus that interest, not the monthly total times the term.

Not financial advice: these calculators provide general educational estimates. Actual loan terms, taxes, insurance, and eligibility depend on your lender and circumstances — confirm figures with a licensed mortgage professional. Everything is processed locally in your browser and never transmitted. See the methodology page for how these tools are built and tested.