Housing
Mortgage Payoff Calculator
Estimate how extra principal payments could shorten your mortgage and reduce total interest. Adjust the assumptions to test different scenarios and use the result as a planning estimate, not a promise.
Housing
Mortgage Payoff Calculator
Result
How to use this calculator
Enter your current mortgage balance, interest rate, remaining term, and the extra amount you're considering adding to each payment. The calculator shows how much time that extra payment removes from your loan and how much total interest it saves. You can run it with different extra payment amounts to find the level that makes the most impact relative to your budget.
Even a small extra payment applied consistently to principal makes a meaningful difference. The reason: any dollar you pay toward principal today eliminates future interest on that dollar for every remaining month of the loan. Early payments eliminate more future interest than later payments, because they have more months ahead of them to compound their savings.
What your result means
The calculator shows two things: how many months you've removed from your payoff timeline, and how much total interest you've eliminated. On a $300,000 mortgage at 7% with 25 years remaining, adding $300/month to principal could cut the remaining term by 7–8 years and save over $100,000 in interest — numbers that often surprise people who assumed extra payments wouldn't matter much.
The savings accelerate as your balance shrinks. Once you've been making extra payments for several years and the balance is significantly lower, the same extra payment eliminates proportionally more time, because there's less balance left to accumulate interest.
What the math leaves out
Extra mortgage payments are effective at saving interest, but they may not be the optimal use of every extra dollar depending on your situation. If your mortgage rate is 4% and you could invest that money and earn 7%, the investment wins on paper. If your rate is 7% and you have credit card debt at 22%, paying the card first wins by an even larger margin. This calculator shows the mortgage payoff math in isolation — pair it with the Pay Debt or Save Calculator to see the full comparison.
Also: confirm with your servicer that extra payments are being applied to principal, not held as a prepaid future payment. Most servicers do this correctly by default, but it's worth verifying on your statement the first time you make an extra payment.
Frequently asked questions
Is it better to make biweekly payments or one extra payment per year?
They're mathematically equivalent. Biweekly payments (26 half-payments per year) equal 13 full payments instead of 12 — one extra payment annually. Some people prefer biweekly because it aligns with paycheck timing and happens automatically. Others prefer making a single lump-sum principal payment when cash flow allows. The outcome is the same if the amounts match.
What if I can't commit to a fixed extra payment every month?
You don't have to. Most mortgages allow variable extra principal payments — you can add $500 one month, nothing the next, and $1,000 the month after. The savings are proportional to what you pay, when. If you have variable income (freelance, sales commissions, bonuses), applying windfalls directly to principal is an effective way to capture the savings without committing to a monthly obligation you might not always meet.
Should I pay off my mortgage early if I have a low rate?
This is a genuine financial planning question, not a math problem with one answer. At low rates (3–4%), the math often favors investing extra money rather than prepaying — expected investment returns historically exceed the guaranteed interest savings. At higher rates (6.5%+), the guaranteed return from prepaying becomes more competitive. The emotional value of owning your home free and clear is real and not captured in any calculation.