Mortgage Payoff Calculator — Pay Off Your Loan Early & Save Interest
A little extra each month can take years off a mortgage. Enter your balance, rate and the time left on your term, add any extra payments, and see your new debt-free date — and exactly how much interest you keep instead of paying.
Your loan & your extras
Advanced options — one-time & yearly extras, payment schedule and start date
One-time and yearly extras, the payment schedule and the schedule start date are already included in the result with their default values — open Advanced options to change them.
🔒 All calculations happen in your browser — no data leaves your device.
What the extras buy you
- On the default loan — $350,000 at 6.50% with 30 years left — adding $200 a month makes you debt-free 74 months sooner: 286 months instead of 360.
- That same $200 a month saves $108,096.83 of interest, cutting it from $446,405.71 to $338,308.88, on a monthly payment of $2,212.24.
- Biweekly payments — half the payment every two weeks — add up to one extra monthly payment a year, so the payoff plan accelerates without a bigger monthly commitment.
Your balance, two ways
The balance month by month — the standard schedule against the same loan with your extras applied. The green line reaches zero first, and the gap between the two curves is interest you never pay.
Month by month: the full schedule
Every payment in the plan, in order — switch between the schedule with your extras applied and the original schedule. In biweekly mode the rows are the two-weekly payments, dated as they fall.
Keep exploring
Three companion tools for the same loan.
How it works
Three steps from balance to debt-free date.
Enter your loan
Your current balance, your interest rate and the years left on the term. The calculator works out the regular monthly payment from those three numbers.
Add your extras
Extra every month, a one-time lump sum in a month you choose, an extra payment once a year — or any mix of the three.
See the saving
The loan is simulated month by month, with and without your extras, so you see the new payoff date, the time saved and the interest saved side by side.
The math behind the payoff
First, the regular monthly payment comes from the standard amortization formula: the payment that clears the balance B over n months at a monthly rate i (annual rate ÷ 12). The loan is then walked month by month: each month, interest is charged on the current balance, everything you pay above that interest — your regular principal plus every extra dollar — cuts the balance, and a smaller balance means less interest next month. That compounding of small cuts is where the saving comes from. The final month is a smaller, exact payment that lands the balance on zero.
Worked examples:
| Loan & extras | Simulation | Result |
|---|---|---|
| $350,000 · 6.50% · 30 yrs · +$200/mo | Payment $2,212.24 · interest falls from $446,405.71 to $338,308.88 | 286 months · saved $108,096.83 · 74 months sooner |
| $200,000 · 5.00% · 20 yrs · no extras | Payment $1,319.91 · 240 months | Interest $116,778.75 |
| $250,000 · 6.00% · 25 yrs · $10,000 once | Payment $1,610.75 · 300 months falls to 275 months | Interest saved $31,723.09 |
Try the default yourself: with no extras the $350,000 loan runs the full 360 months and costs $446,405.71 in interest. Adding $200 a month — about the cost of a streaming bundle and a pizza — ends it in 286 months, because every extra dollar skips years of interest charges on that dollar.
Go deeper
Why timing matters — and the checks to run before you send extra money.
Why early extras hit interest hardest
Interest is charged on whatever balance is standing, so a dollar of principal removed today stops being charged for in every remaining month:
- Front-loaded interest: in the early years most of each payment is interest, which is exactly when extra principal does the most work — it shrinks the base that all future interest is calculated on.
- Early beats late: a $10,000 lump sum in month 1 saves far more than the same $10,000 in year 10, because it avoids a decade of interest on that slice of the loan.
- Monthly extras compound quietly: each month’s extra lowers the next month’s interest a little, so the balance curve bends further and further away from the standard schedule.
- Every extra dollar is principal: mark extra payments “apply to principal” with your lender so they are not treated as early installments.
Four checks before you pay extra
Paying a mortgage down early is rarely a bad move, but the order you do things in matters:
- Prepayment penalties: most modern mortgages have none, but check your loan terms — a penalty can eat the saving on large lump sums.
- Pricier debts first: a credit card at 25% costs more per dollar than a mortgage at 6.5% — clear expensive debts before accelerating the cheap one.
- Keep an emergency fund: money inside a mortgage is illiquid. A cash buffer of a few months’ expenses protects you from borrowing at card rates when life happens.
- Retirement match: if an employer matches retirement contributions, that match is an instant 100% return — claim it before extra mortgage payments.
Why early extras hit interest hardest
Interest is charged on the balance, so an extra dollar in year one saves interest on every remaining payment, while the same dollar in year fifteen saves far less. The companion guide quantifies it: $200 a month on a $300,000 loan at 6 percent saves roughly $91,000 and nearly seven years.
Four checks before you pay extra
Check for prepayment penalties, confirm extras are applied to principal rather than to future payments, keep an emergency fund liquid, and clear higher-rate debt first. An extra applied to next month payment saves nothing.
Frequently asked questions
Quick answers about paying a mortgage off early.
How does paying extra on my mortgage save interest?
Interest is charged each month on the balance still standing. An extra payment comes straight off that balance, so every future month’s interest charge shrinks a little — and those savings stack up month after month. Early extras save the most, because they stop interest being charged on that money for the longest time.
How much can I save by paying $200 extra a month?
On the calculator’s example loan — $350,000 at 6.50% with 30 years left — paying $200 extra a month ends the loan in 286 months instead of 360 and saves $108,096.83 of interest: 74 monthly payments you never make. Your own saving depends on your balance, rate and how early you start.
Is it better to pay extra monthly or as one lump sum?
For pure interest saved, earlier wins: a lump sum paid today removes that principal from every remaining interest charge, while the same money spread monthly removes it gradually. In practice, monthly extras suit steady budgets and lump sums suit bonuses and windfalls — many people do both. Either way, tell your lender to apply extras to principal.
Does this calculator include taxes and insurance?
No. The simulation covers principal and interest only, because taxes, insurance and HOA dues are not part of the loan balance and do not shrink as you pay the loan down. Your total monthly outlay will be higher than the payment shown here, but the payoff date and interest figures are unaffected.
Will extra payments lower my monthly payment?
Not by themselves. On a standard fixed-rate mortgage your required payment stays the same and the extras shorten the term instead — you finish early rather than pay less each month. If you want a lower payment after a large lump sum, ask your lender about a recast, where the loan is re-amortized over the remaining term at the same rate, usually for a fee.
Should I invest instead of paying off my mortgage early?
It comes down to rates and risk. Paying extra earns a guaranteed return equal to your mortgage rate, with no market risk. Investing might return more on average, but it is not guaranteed, and the comparison should be after tax and after clearing any higher-rate debts. This calculator shows the mortgage side of the equation; the choice itself depends on your circumstances and risk tolerance.
How do I make sure extra payments go to principal?
Instruct the lender in writing that extras apply to principal, and check the next statement: the balance should fall by the extra amount plus the scheduled principal. If it does not, contact the servicer.
Does a biweekly schedule really save money?
Yes, if it delivers 26 half-payments a year, which is 13 monthly payments. The thirteenth payment is the saving mechanism. A self-managed extra monthly payment a year achieves the same result free.
What is recasting?
Re-amortising the loan at the lower balance for a fee, which lowers the scheduled payment instead of shortening the term. It suits borrowers who want payment relief rather than an earlier payoff.
Related guides
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More tools for loans and home finance.
Disclaimer
This calculator is for information only and is not financial advice. Results are estimates from a month-by-month amortization of the figures you enter: they assume a fixed rate, on-time payments and extras applied to principal, and they exclude property taxes, insurance, HOA dues and any prepayment penalty. Confirm your payoff figures, extra-payment rules and any penalties with your lender before acting.