15 Year Fixed Loan Calculator

What a 15-year fixed loan is

A 15-year fixed loan pays off in exactly 180 monthly payments at one interest rate that never moves. The payment is the same in month 1 and month 180; what changes is the split inside it. Early payments lean heavily toward interest: on a $300,000 loan at 6.60%, the first payment carries $1,650.00 of interest and $979.84 of principal, and the split keeps sliding toward principal every month after.

The payment quoted here is principal and interest. Property taxes, homeowners insurance and any HOA fee are billed on top, so the check you write to the servicer will be larger. Treat every figure on this page as the loan itself, before those extras.

The rate matters as much as the term. Freddie Mac's Primary Mortgage Market Survey put the 15-year average at 6.60% and the 30-year average at 7.24% for the week of October 29, 2026. Those two numbers drive every comparison below. Lenders quote rates daily, so treat 6.60% as a reference point rather than a promise, and type the rate from your own Loan Estimate into the calculator above for a personal answer.

Who picks this term? Buyers who can absorb the higher payment in exchange for the lower rate and the fast payoff, and owners refinancing out of a 30-year loan they have held for years: moving from year 8 of a 30-year schedule into a fresh 15-year loan often raises the payment far less than the term change suggests, because the old balance has already come down. The payment you get depends on the balance you bring, which is why the loan amount box above is the first number to change.

The payment at 6.60%, by loan size

At the October 29, 2026 survey average of 6.60%, the 15-year payment works out to roughly $8.77 a month for every $1,000 borrowed. The table runs the standard amortization formula across five common loan sizes. Total interest is the payment times 180 minus the amount borrowed.

Interest takes 36.6 cents of every dollar paid on each of these loans, because the rate and the term stay fixed even as the size moves. That share is the quiet cost of borrowing: on the $300,000 loan, interest is $173,371.64 of the $473,371.64 that leaves your account over 15 years. The weekly averages come from Freddie Mac's Primary Mortgage Market Survey archive, and the same 15-year series is published as the FRED series MORTGAGE15US maintained by the St. Louis Fed.

15 years against 30 years: the dollar gap

The same $300,000 borrowed, split two ways, shows what the shorter term buys and what it costs. The 15-year loan at 6.60% asks for $2,629.84 a month. The 30-year loan at the 7.24% survey average asks for $2,044.49. The gap is $585.35 a month, which is 585.35 / 2,629.84 = 22.3% more cash out the door every month for the shorter loan.

The payoff for paying it is far larger than the gap suggests. The 15-year borrower pays $173,371.64 of interest in total; the 30-year borrower pays $436,017.99. Choosing the shorter term keeps $262,646.35 in your pocket over the life of the loan, and the house is fully yours 15 years sooner.

Part of that saving comes from the lower 15-year rate itself, and part from the compressed schedule. Both effects push the same way: less time for interest to accrue, and a balance that falls faster from the first month.

Where the saving comes from: the balance race

Interest accrues only on the balance still owed, so the whole trick is forcing the balance down fast. After five years, the 15-year borrower owes $230,571.75 while the 30-year borrower still owes $283,107.16 of the same $300,000. After ten years the split is $134,086.55 against $258,872.06.

Half the principal on the 15-year loan is gone by month 112. The 30-year loan does not reach that line until month 263, more than a decade later. And at month 180, when the 15-year borrower makes a final payment and walks away clear, the 30-year borrower still owes $224,103.48, which is 224,103.48 / 300,000 = 74.7% of the original amount, with 180 payments still ahead.

This is also why a 15-year loan is a strong fit for owners who expect to sell one day. Equity is cash at the closing table, and the shorter term piles it up at nearly twice the pace of the standard 30-year schedule.

The same race in dollar terms: by month 60 the 15-year borrower has retired $69,428.25 of principal while the 30-year borrower has retired only $16,892.84. That difference, $52,535.41, is the equity edge at the five-year mark, before any change in home value. It is also the cushion if a sale ever happens at the wrong time, since closing costs come out of equity and a thin equity line can turn a sale into a loss.

Extra payments: months off the end

The 15-year schedule already front-loads principal, and an extra payment moves the finish line again. Every extra dollar goes straight to principal, so each one stops accruing interest for the rest of the term. The table shows what a standing extra payment does to the $300,000 loan at 6.60%, with the required payment left unchanged.

An extra $100 a month is $1,200 a year, and it buys back 10 months of payments plus $11,790.99 of interest. Step up to $250 and the loan ends at the 13-year mark instead of the 15-year mark. Before you commit to a standing extra, confirm two things with your servicer: that the money is applied to principal in the month it arrives, and that the loan carries no prepayment penalty. Most fixed-rate home loans today have none, but private and specialty loans sometimes do.

One classic pattern is the thirteenth payment: sending one twelfth of the regular payment as an extra each month. On this loan that is $219.15 a month, which ends things at month 158, more than a year and a half early, and saves $23,819.17 of interest. Splitting the annual bonus into monthly pieces works better than waiting for year end, because every dollar stops working against you the month it lands.

The income the payment asks for

Lenders size a housing payment against gross income. A common guideline caps housing near 28% of gross monthly pay, though every lender and loan program draws its own line. On that guideline, the $2,629.84 payment on the $300,000 loan needs 2,629.84 / 0.28 = 9,392.29 a month before tax, about $112,700 a year.

That figure covers principal and interest only. Add property tax, homeowners insurance and any HOA fee and the qualifying income climbs, sometimes by hundreds of dollars a month. The CFPB's debt-to-income explainer (CFPB, 2024) walks through how lenders count these obligations when they size a loan.

Stretching to a 15-year payment is easier to judge once you list every recurring housing cost, not just the loan payment. If the full housing load passes a third of gross pay, the 30-year term or a smaller loan amount may be the sturdier choice.

Lenders also look at the back-end ratio, which adds every monthly debt payment to the housing cost: car loans, student loans, credit card minimums and the new mortgage all count. A buyer with a $600 car payment does not qualify on housing alone; the full stack has to fit under the lender's ceiling, which for many conventional loans sits in the mid-40s as a percent of income. List your monthly debts before shopping so the 15-year payment is judged against reality.

When the 15-year loan is the wrong fit

The 15-year payment runs about 22% higher than the 30-year payment here, and that gap lands every month for 15 years. If your income is irregular, if you carry credit card balances at 20% or more, or if your emergency fund is thin, the smaller 30-year payment with voluntary extra principal can be the safer structure. You pay the same total when times are good and fall back to the lower required payment when they are not.

Also weigh where the spare cash could go. If your employer matches 401(k) contributions, the match usually beats prepaying a 6.60% loan dollar for dollar. And if a job change or a move is likely within a few years, remember the 15-year loan builds equity fast: after three years its balance is $261,108.94 against $290,602.79 on the 30-year, which means more cash out at closing when you sell. Run your own numbers in the calculator, compare against your full budget, and pick the term you can hold through a bad year, not just a good one.

An adjustable-rate mortgage is the other competitor: it starts cheaper than the 15-year fixed, but the payment can rise once the fixed period ends, and no chart on this page can predict where it lands. A 15-year fixed trades a higher starting payment for certainty. If the difference between the two monthly amounts would strain your budget in a normal month, the fixed payment is the safer price to pay.