Free Mortgage Calculator Online

Buying a home starts with one number that determines whether the rest of the budget works: the monthly mortgage payment. This mortgage calculator takes a home price, a down payment percentage, an interest rate, and a loan term, and returns the monthly principal-and-interest payment instantly, along with the loan amount, the dollar value of the down payment, total interest over the full term, and total cost of the home once every payment is added up. Unlike a generic loan calculator, it's built around the specific shape of a home purchase — a percentage-based down payment reducing the amount actually financed, and a choice between the three loan terms lenders commonly offer.

How the Calculator Works

Four inputs sit at the top: home price (a dollar figure), down payment (entered as a percentage of the home price, not a flat dollar amount), interest rate, and a term selector with three buttons — 15, 20, and 30 years — so switching between them is a single click rather than retyping a number.

• Down payment as a percentage. Entering 20 rather than a dollar figure means the down payment amount and the resulting loan size recalculate automatically whenever the home price changes, without needing to redo the percentage math by hand each time you adjust the price.
• Headline monthly payment. The largest number on the results panel is the monthly principal-and-interest payment, sized and colored to be the first thing you see after entering a scenario.
• Four supporting figures. Below the headline number, four smaller cards show the loan amount (home price minus down payment), the down payment in dollars, total interest paid over the full term, and the total cost of the home including interest.
• Principal-versus-interest bar. A horizontal split bar shows what percentage of the total amount paid over the life of the loan is principal versus interest, giving a quick visual sense of how much of the sticker price ends up being the cost of borrowing.

The calculation itself is the standard amortization formula applied to the financed amount (home price minus down payment) rather than the full purchase price — a $400,000 home with 20% down finances $320,000, and the monthly payment, total interest, and total cost all derive from that reduced figure, not the sticker price.

A metered API version of this calculation is documented at /docs, and it goes a step further than the browser tool: alongside home price, down payment, rate, and term, the API accepts optional annual property tax and annual homeowners insurance figures, and returns a fuller breakdown — monthly principal-and-interest, monthly tax, monthly insurance, and a combined monthly payment covering all three. The browser calculator on this page focuses on principal and interest alone; a developer who needs the tax-and-insurance-inclusive monthly figure (commonly called PITI) can get it from the API endpoint directly rather than adding those two numbers by hand.

Why This Matters Before You Shop

A home price alone tells you almost nothing about affordability — the same sticker price can produce wildly different monthly payments depending on rate, term, and down payment:

• Setting a realistic house-hunting budget. Knowing what monthly payment a given price range actually produces, before touring homes, keeps the search focused on properties that fit rather than ones that look affordable on price alone.
• Deciding how much to put down. Comparing a 10% down payment against a 20% one on the same home shows the tradeoff directly — a smaller loan amount, a smaller monthly payment, and less total interest, weighed against tying up more cash upfront.
• Choosing between a 15-year and a 30-year term. A 15-year mortgage carries a meaningfully higher monthly payment than a 30-year one on the same loan amount, but a dramatically lower total interest cost — running both terms side by side turns that abstract tradeoff into two concrete dollar figures.
• Pre-negotiation confidence. Walking into an offer or a lender conversation already knowing what a given price and rate combination costs monthly removes a layer of uncertainty from a process that already has plenty of it.
• Rate-shopping across lenders. Two lenders quoting rates a quarter-point apart on the same loan amount and term produce a real difference in monthly payment and total interest over 30 years — plugging both rates into the same calculator surfaces the actual gap rather than trusting each lender's own framing of "how small" the difference is.
• Deciding whether to buy now or wait for a better rate. Rates move over time, and holding off on a purchase in hopes of a lower rate later carries its own cost in the form of rising home prices or lost time. Running the same home price at a slightly higher and slightly lower hypothetical rate shows exactly how much waiting would need to save on rate before it outweighs paying today's price.

None of this replaces an actual conversation with a lender — it's a way to walk into that conversation already knowing roughly what range of numbers to expect, which tends to make the process faster and less confusing on both sides.

Technical Deep Dive: What the Monthly Payment Actually Contains

The figure this calculator produces is principal and interest only — the "P&I" portion of what many homeowners call their full mortgage payment. A complete monthly housing cost for an owner with a mortgage typically also includes property tax and homeowners insurance (together with P&I, this four-part total is the acronym PITI), and, for a down payment under 20%, private mortgage insurance (PMI) on top of that. This calculator computes P&I precisely using the standard amortization formula on the financed amount; it does not add tax, insurance, or PMI into the on-page monthly figure, so treat the headline number here as the loan-servicing portion of the payment, not the full amount that will actually leave a bank account each month once escrow is involved.

The reason the down payment percentage matters so much to the total cost isn't just the smaller starting loan — it's that every dollar of principal not borrowed is a dollar that never accrues interest across the entire term. Increasing a down payment from 10% to 20% on a $350,000 home reduces the loan amount by $35,000, and over a 30-year term at a typical rate, the interest saved on that $35,000 alone is a meaningfully larger number than $35,000 itself, because that principal would otherwise have compounded interest charges for up to three decades.

An honest look at what different estimation methods actually cover:

Method	Computes P&I correctly	Includes tax & insurance	Lets you compare terms instantly
Rule-of-thumb price multiplier ("2.5x income")	No — ignores rate and term entirely	No	No
Lender pre-qualification estimate	Yes, for that lender's rate	Often, as a rough add-on	Requires a new inquiry per scenario
Real estate listing site's built-in estimator	Usually, with generic default assumptions	Sometimes, with local averages	Limited to that one listing's numbers
This mortgage calculator	Yes, exact P&I on the financed amount	P&I only in the browser tool; full PITI available via the API	Yes, instantly on any term change

Comparing Ways to Estimate a Home Payment

Several tools claim to help estimate a mortgage payment, with real differences in what they cover:

• Listing-site payment estimators. Convenient because they're attached to the property you're already looking at, but usually built around default assumptions about rate and tax that may not match your actual situation.
• A lender's official pre-approval. The most accurate number you can get, since it reflects your actual creditworthiness and their actual rate offer, but it takes time, a credit check, and paperwork — not something to run five times while comparing hypothetical scenarios.
• Spreadsheet-based amortization models. Flexible and capable of including every cost component if built carefully, but building one correctly from scratch is a bigger project than a home-price comparison usually justifies.
• A dedicated browser mortgage calculator. Purpose-built for exactly this comparison — home price, down payment, rate, and term in, monthly payment and total cost out, with no setup and no application required.

How Your Mortgage Numbers Are Handled

Every figure entered here — home price, down payment percentage, rate, and term — is calculated locally in your browser and never transmitted to a server or stored anywhere. There's no sign-in, no saved history, and closing the tab clears the scenario instantly. Every visitor runs the identical calculation with no restriction on how many times it's used.

Common Questions About Mortgage Payments

Does the monthly payment shown here include property tax and homeowners insurance?

Not in the browser tool — the figure on this page is principal and interest only. A fuller monthly total that folds in property tax and insurance (the full PITI figure) is available through the metered API endpoint linked above, which accepts those two figures as optional inputs and returns the combined monthly amount.

Does this calculator account for private mortgage insurance on a small down payment?

No. PMI, typically required when a down payment is below 20% of the home price, isn't included in this calculation. It's a separate monthly cost set by the lender and mortgage insurer based on loan-to-value ratio and credit profile, factors outside what this calculator computes.

Should I choose a 15-year or a 30-year mortgage term?

That depends on how much monthly payment your budget can absorb versus how much total interest you're comfortable paying over time — a 15-year term cuts total interest substantially but raises the required monthly payment, while a 30-year term does the opposite. Running the same home price and rate through both term buttons shows the exact numbers for your specific scenario rather than a generic rule of thumb.

How much does increasing my down payment actually lower my monthly payment?

It lowers the loan amount by the exact dollar amount of the additional down payment, and the monthly payment drops proportionally to that smaller loan amount under the same rate and term. Testing a few different down payment percentages on the same home price shows the specific dollar reduction rather than a percentage-based approximation.

Is the rate I enter here the rate I'll actually be offered?

Not necessarily — this calculator computes the correct payment for whatever rate you enter, but the rate a specific lender ultimately offers depends on credit score, loan-to-value ratio, loan type, and current market conditions, none of which this tool evaluates. Use it to test how different rate scenarios affect affordability, then compare that against actual quotes once you're ready to apply.

Why does a small change in interest rate make such a big difference over 30 years?

Interest compounds against the outstanding balance every month for the entire term, so even a small rate difference multiplies across 360 monthly payments on a large loan balance. A quarter-point rate difference on a $300,000, 30-year loan typically shifts total interest by five figures, which is why comparing rates precisely, rather than rounding to "close enough," matters more the larger and longer the loan is.

Why do two homes with the same price sometimes have very different total mortgage costs?

Because total cost depends on far more than sticker price — the rate offered, the term chosen, and the down payment percentage each move the total interest figure independently. Two identically priced homes bought with different down payments or financed at different rates can easily differ by tens of thousands of dollars in total interest over the life of the loan, even though the purchase price on the listing was the same.

Related Tools

For a home loan without the property-specific down-payment framing — a personal loan, an auto loan, or any other fixed-rate borrowing — the general-purpose Loan Calculator uses the same underlying formula with inputs suited to non-mortgage lending. To see every single monthly payment broken into principal and interest rather than just the summary totals shown here, the Amortization Schedule Calculator builds the full period-by-period table for any loan amount, rate, and term. If the comparison is about how savings or an investment grows rather than how a mortgage gets paid down, the Compound Interest Calculator covers that side of personal finance, and buyers factoring in tax-inclusive pricing on a property purchase abroad can reference the VAT Calculator for that separate calculation.