30 Year Mortgage Calculator: Payment, Interest and Equity Tables

Payment scales in a straight line with the amount borrowed, so this table is the fastest way to see where your budget lands. The last column shows the same loan on a 15-year term at Freddie Mac's 6.73% average for the same week, for comparison.

A rule of thumb falls out of the table: at 7.40%, every $50,000 borrowed over 30 years adds about $346 to the monthly payment. At this rate the lifetime interest on a 30-year loan is roughly 1.5 times the amount borrowed, so a loan kept to the end costs about two and a half times the amount borrowed. These are principal-and-interest figures only; property tax, homeowners insurance and any mortgage insurance come on top, and our mortgage calculator with PMI, taxes and insurance adds them in.

Rate quotes for the same borrower can differ by half a point or more between lenders, and the market moves that much in a few months. On a $400,000, 30-year loan, here is what each step costs:

Half a point on this loan is worth roughly $130–$140 a month and roughly $47,000–$50,000 over the full term. Two practical conclusions follow. Getting several written loan estimates on the same day is worth real money — the CFPB's loan options guide explains how to compare them. And a year's movement matters too: the same $400,000 at last October's 6.30% average would have cost $2,475.89 a month, $293.63 less than today.

Most 30-year mortgages are not kept for 30 years. People move, refinance or sell long before the last payment, which makes the balance after five or ten years a more useful planning number than the lifetime interest total. On the $400,000 loan at 7.40%:

• After 3 years you have paid $99,703 in total, of which $12,166 reduced the loan. Balance: $387,834.
• After 5 years: $21,908 of principal repaid, $144,263 of interest paid. Balance: $378,092.
• After 7 years: $33,199 of principal, $199,440 of interest. Balance: $366,801.
• After 10 years: $53,589 of principal, $278,753 of interest. Balance: $346,411 — still 87% of the original loan.

That slow start is not a flaw in any one lender's loan; it is how amortization works when the payment is spread thin over 360 months and interest is charged on a large balance. It has two consequences worth planning for. If you expect to sell within five years, nearly all the equity you walk away with will come from your down payment and any rise in the home's value, not from paying down the loan. And because selling costs come out of that equity, a short hold on a 30-year loan can leave less cash than expected. The month-by-month detail is on our 30-year mortgage amortization schedule, and the general mechanics on the mortgage amortization schedule guide.

Lenders judge affordability with a debt-to-income ratio: all monthly debt payments divided by gross monthly income. The Consumer Financial Protection Bureau's explanation of DTI notes that different loan products and lenders set different limits, so there is no single cut-off to aim for. What you can do is see where the payment sits before anyone else does.

The $2,769.52 principal-and-interest payment on $400,000 is 34.6% of a $8,000 gross monthly income, 27.7% of $10,000, and 23.1% of $12,000. Every other debt — car loans, student loans, minimum card payments — adds to the ratio, and so do taxes and insurance once they are included in the housing payment. If the number makes you uneasy at the P&I stage, it will look worse with escrow added; that is a signal to look at a smaller loan amount in the table above rather than to hope the lender says yes.

The strongest argument for a 30-year term is that its required payment is a floor, not a ceiling. You can pay more whenever you can afford to, and fall back to the minimum when money is tight. A 15-year loan does not give you that option.

The cost of that flexibility is the rate. To pay off the $400,000 30-year loan in 15 years at its 7.40% rate, you would need to send $3,685.36 a month and would pay $263,364 in interest. A true 15-year loan at the 6.73% average needs $3,535.20 a month and costs $236,337. So the flexibility costs about $150 a month — around $27,000 over 15 years — if you are disciplined enough to pay the higher amount every month.

A smaller commitment still moves the needle. An extra $100 a month toward principal on the same 30-year loan retires it in 320 payments instead of 360 and cuts total interest from $597,027 to $516,407. Test your own extra amount in the calculator above or on the mortgage calculator with extra payments; for a side-by-side of the two terms, see the 15 year vs 30 year mortgage calculator and the 15 year mortgage calculator.

The calculator above asks for more than a loan amount and a rate, and each extra field exists because it changes what you will really pay. In rough order of impact:

1. Home price and down payment. Together they set the loan amount, and the loan amount drives everything in the tables above. Moving from 10% down to 20% down on a $450,000 home cuts the loan from $405,000 to $360,000 and the 7.40% payment by about $312 a month.
2. Rate. Covered above: about $130–$140 a month per half-point on $400,000. Enter the rate from your own loan estimate, not the weekly average.
3. Mortgage insurance. With less than 20% down on a conventional loan you will usually pay private mortgage insurance. The CFPB explains that you can ask to cancel PMI when the balance is scheduled to reach 80% of the home's original value, and that the servicer generally must end it automatically at 78%. On a $405,000 loan against a $450,000 home at 7.40%, the schedule reaches 80% ($360,000) at payment 105 — almost nine years in — and 78% ($351,000) at payment 120. That long tail is a direct result of the slow early amortization described above.
4. Property tax and insurance. They do not affect the loan's amortization, but they are part of the monthly bill and often of the escrow account your servicer runs. Use your county's actual tax figure and a real insurance quote rather than a national average.
5. Extra payments. The one input entirely under your control after closing, and the only one that shortens the 360-month schedule.

If you only have time to get one number right, make it the rate on a written loan estimate: everything else on this page scales from it.

The 30-year fixed is the default, not the right answer for everyone. It tends to fit poorly in three situations. If you can comfortably afford the 15-year payment and will not use the flexibility, you are paying for an option you will never exercise. If you are close to retirement and want the house paid off while you still have earned income, a 30-year schedule simply runs too long. And if you expect to move within a few years, compare the total cost of the 30-year fixed with shorter fixed periods on an adjustable loan using real quotes rather than averages.

Equally, there are cases where the 30-year term is clearly better: when the lower payment is what keeps your emergency fund intact, when your income is variable, or when a shorter term would push your debt-to-income ratio to a level a lender will not accept. The point of running the numbers is to decide on purpose.

I calculated every payment, balance and interest total on this page with the standard fixed-rate amortization formula — M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], with r as the monthly rate and n = 360 — using the same routine that runs this site's calculators, and confirmed the 3-, 5-, 7- and 10-year balances by stepping through the schedule month by month. The 7.40% (30-year) and 6.73% (15-year) rates, the prior week's 7.28% and the year-earlier 6.30% are Freddie Mac's Primary Mortgage Market Survey averages for the week of October 8, 2026, read on October 12, 2026. Averages are not quotes: your rate depends on your credit, down payment, points and the lender. For the full tool with taxes, PMI, extra payments and a downloadable schedule, go to the mortgage amortization calculator homepage.