About the Mortgage Payoff Calculator
Most mortgages front-load interest, so in the early years nearly all of your payment goes to the lender and very little reduces the balance. Paying extra principal changes that: every extra amount shortens the loan and avoids all the future interest on it. This calculator takes your balance, rate and remaining term, works out your normal payment and then shows what happens if you add a monthly amount, a one-off lump sum or both. You see the new payoff time, how many months you save and how much interest you avoid, next to the figures for the normal schedule.
Updated October 2026
How to use the Mortgage Payoff Calculator
- 1Enter your current balance, interest rate and the years left.
- 2Enter an extra monthly amount you could pay.
- 3Optional: enter a one-off lump sum to pay now.
- 4Read the time and interest saved.
- 5Compare payoff times and interest with and without the extra payments.
Worked example
A 250,000 balance at 6 percent with 25 years left has a normal payment of about 1,611 and would cost about 233,200 in interest over 300 months. Adding 200 a month means the loan is paid off in 236 months, about 19 years 8 months, with total interest of 175,600. That is 64 months sooner and 57,600 less interest, for 47,200 of extra payments over that time.
One more idea is to combine extra payments with a refinance. If rates fall, refinancing into a shorter term at a lower rate can cut the interest without raising your payment much, and you can keep paying the old amount to shorten it further. Compare the closing costs with the interest saved, and make sure you will stay in the home long enough to recover them, which is often three to five years.
Strategies that work
- Round up your payment to the next 100.
- Put bonuses and tax refunds toward the balance.
- Make one extra payment a year.
- Refinance to a lower rate and keep paying the old amount.
- Start extra payments early, when the effect is largest.
Think about the whole picture
Before sending every spare pound or dollar to the mortgage, make sure you have an emergency fund, no high-interest debt and access to money if you need it, since home equity is hard to get back out. Also consider whether you would rather use the money for retirement savings that attract employer matching or tax benefits.
Related tools
The Mortgage Calculator shows the normal schedule, the Refinance Calculator tests a new loan, the Loan Calculator handles other debts and the Emergency Fund Calculator helps you decide how much cash to keep.
Features
- Time saved in years and months
- Interest saved
- Normal and faster payoff side by side
- Extra monthly and lump sum options
- Fixed-rate loan assumption
- Works in any currency
Frequently asked questions
How much does an extra payment save?
On a 250,000 balance at 6 percent with 25 years left, adding 200 a month cuts the payoff time by 5 years 4 months and saves about 57,600 in interest. The earlier in the loan you pay extra, the more it saves.
Should I pay extra or invest instead?
It depends on your mortgage rate compared with what you expect to earn after tax and risk. Paying off a 7 percent mortgage is a guaranteed 7 percent return. If your rate is very low, investing might earn more, but with risk.
Will my lender apply the extra to principal?
Usually only if you tell them. Some lenders apply extra money to the next payment instead. Mark the payment as principal only, and check the next statement to confirm the balance dropped as expected.
Are there penalties for paying early?
Some loans have prepayment penalties, especially in the first few years, and some countries limit how much extra you can pay without a fee each year. Read your loan agreement or ask your lender before making large extra payments.
What about bi-weekly payments?
Paying half your monthly amount every two weeks gives 26 half-payments, equal to 13 full payments a year, one more than monthly. You can model it by adding one-twelfth of a payment as the extra monthly amount.
Does the calculator assume a fixed rate?
Yes. With a variable rate, the future payment can change. Use the current rate for a rough picture and re-run the numbers when the rate changes.