$100,000 Loan for 15 Years Calculator

What a $100,000 loan over 15 years costs

Enter a rate and this page prices a fixed loan of $100,000 paid back in 180 equal monthly payments. At a 6% annual rate the payment is $843.86 per month, and the total interest over the 15 years is $51,894 on top of the $100,000 you borrowed. For a real world anchor, the average 15 year fixed mortgage rate in the United States was 6.60% in late October 2026, per the Freddie Mac survey series published on FRED, so a quote near $844 a month is what a well qualified borrower at that average would see for principal and interest.

The same loan priced at 7% costs $898.83 a month and $61,789 in interest. At 8% it is $955.65 a month and $72,017 in interest. Those three rates bracket most personal loan, auto loan and mortgage quotes that show up in 2026, which is why this page is built around them. Everything below works the same for any fixed rate amortizing loan: a car loan, a personal loan, a home improvement loan or a mortgage before taxes and insurance are added.

The monthly payment formula behind the number

The standard amortizing payment formula is M = P x r / (1 - (1+r)^-180), where P is the principal, r is the monthly rate and 180 is the number of monthly payments in 15 years. The monthly rate is the annual rate divided by 12, so 6% a year gives r = 0.005.

Run the numbers at 6%: (1.005)^180 comes to about 2.4541, so the denominator is 1 - 1/2.4541 = 0.59252. The numerator is $100,000 x 0.005 = $500. Divide $500 by 0.59252 and you get $843.86. The payment is set so that the last of the 180 payments brings the balance to exactly zero. Pay more than that and the loan retires early; pay less and it never does, because $500 of new interest arrives every month at the start.

One detail that trips people up: the formula assumes the rate stays fixed for all 180 months and that every payment lands on schedule. An adjustable rate loan, a balloon structure or a loan with a large final payment does not fit this page, and neither does a revolving line of credit where the payment floats with the balance.

Rate sensitivity: what one point costs

Each extra point on the rate adds about $55 to $57 to the monthly bill and roughly $9,900 to $10,200 to the lifetime interest. Going from 6% to 8%, two full points, raises the payment by $111.79 a month and the total interest by $20,123. That is a fifth again as much interest for exactly the same $100,000 borrowed over exactly the same 15 years.

This is why shopping the rate is worth the paperwork. A borrower who takes three quotes and lands 6.5% instead of 7.5% keeps about $10,000 over the life of the loan, and the credit report pull costs nothing but a few days of inquiries. On a 15 year schedule the rate does more work than on a 30 year one, because there are fewer months for the higher rate to compound against a slow falling balance.

10, 15, 20 and 30 year terms compared

Stretching the same $100,000 from 15 to 30 years drops the payment by $244.31 a month but nearly doubles the total interest, from $51,894 to $115,838. Shortening it to 10 years costs $266.35 more each month and saves $18,669 in interest. The 15 year term sits in the middle: a payment most households can carry against a 30 year quote, with roughly half the lifetime interest.

Two cautions when reading that table. Lenders usually price longer terms at higher rates, so the real gap between a 30 year and a 15 year quote is wider than the table shows; the 15 year average ran about a point under the 30 year average through 2026 in the Freddie Mac survey data. And the right term is a cash flow decision, not only a math one. A payment you can always make beats a payment that saves interest but breaks in month 20.

Where each early payment goes

Amortization front loads the interest. The CFPB explains it plainly: the lender charges interest on the balance you still owe, so the first payments on a fresh $100,000 loan are mostly interest, and the share that goes to principal grows as the balance falls. At 6%, the first $843.86 payment splits $500.00 to interest and $343.86 to principal. Interest is 59% of the check even though it is month one of 180.

Payment 43 is where principal first outweighs interest at 6%, a little under three years in. Halfway through the schedule, after 90 payments and $76,000 paid, the balance still stands at $61,037, or 61% of what you borrowed. The last payment is nearly all principal, $839.66 of it against $4.20 of interest. Nothing shady is happening; the interest each month is the monthly rate times whatever is left, and it takes years for the falling balance to show up in the split.

Paying $100 or $200 extra each month

Because interest is charged on the live balance, every extra dollar sent to principal stops charging interest for the rest of the term. That makes small overpayments surprisingly powerful on a 15 year schedule.

An extra $100 a month, $944.86 total instead of $843.86, retires the loan in 152 payments, two years and four months early, and cuts $9,115 from the interest bill. An extra $200 a month finishes in 131 payments, four years and one month early, and saves $15,437. Put differently, the $200 version costs $35,800 of extra payments and buys back $15,437 of interest plus four years of not having the loan at all.

One mechanical warning: mark the extra amount as principal only. Many servicers apply anything over the billed amount to the next scheduled payment instead, which advances the due date but leaves the balance, and the interest, exactly where it was. The payment portal usually has a principal only option, and a short written instruction works if it does not.

How this page differs from our other loan tools

This site already has two broader loan tools, and it helps to know which one answers which question. The loan calculator compares two loan quotes side by side, so it is the tool for choosing between offers. The house loan monthly payment calculator breaks a mortgage payment into principal, interest, taxes and insurance, so it is the tool for estimating what a house costs per month all in.

This page narrows to one scenario, $100,000 over 180 payments, and goes deep on the questions that scenario raises: what each rate point costs, how a 15 year term trades against 10, 20 and 30 years, where the payment split sits in the early months, and what an extra $100 or $200 buys. If those are your questions, the single scenario is faster than a general tool and the writeup around it does the comparing for you. The widget also shows the first payment split and the payoff date with overpayments, which the other two tools do not print.

For background on how lenders set and quote rates, the Federal Reserve publishes consumer oriented guides on mortgage shopping and closing costs at federalreserve.gov, and the Freddie Mac Primary Mortgage Market Survey is the weekly series most lenders benchmark against.

Assumptions and limits

The numbers on this page assume a fixed rate, 180 equal monthly payments, no origination fees, no prepayment penalty and no escrow. Real quotes add mortgage insurance, property taxes, homeowners insurance and closing costs on top of the $843.86 figure, so treat the output as the principal and interest core of the payment, not the whole bill. If your lender quotes an APR that folds fees into the rate, enter the note rate for the payment math; the APR is for comparing offers, not for computing a schedule.

Extra payment results assume the overpayment starts with the first payment and continues every month until the loan closes. Starting the $100 overpayment in year 5 instead of month 1 recovers less than the full $9,115, because the middle years of the schedule are exactly where the balance is falling fastest. Rounding also matters at the edges: lenders amortize to the cent on their own systems, so your payoff statement may differ from this page by a few dollars in the final months. None of this is lending advice; it is arithmetic you can check against your own disclosure forms.