Mortgage Payoff Calculator
How many years are left, when you'll be mortgage-free, and how to get there faster
This one is for people who already have a mortgage rather than those shopping for one. Give it your current balance, your interest rate and what you pay each month, and it works out the date you'll be mortgage-free, the interest still to come, and — the part most people are really after — how much sooner you'd finish, and how much you'd save, by overpaying.
Your Mortgage
📉 Your Balance Over Time
Roughly what you'll still owe at each point (including any overpayments above).
How to work out when your mortgage will be paid off
The number of months left on a mortgage depends on three things: the balance you still owe, your interest rate, and how much you pay each month. Each payment first covers that month's interest, and whatever is left chips away at the balance — so the more you pay (or the lower your balance and rate), the sooner you're done.
The formula is n = −ln(1 − (P × r) ÷ M) ÷ ln(1 + r), where P is your balance, r is the monthly interest rate (annual rate ÷ 12) and M is your monthly payment. Overpaying increases M, which shrinks n dramatically because you cut the balance faster and pay interest for fewer months — that's why even a small monthly overpayment can knock years off and save thousands.
Related Calculators
🏠 Mortgage Repayment Calculator — for a new mortgage · 💷 Loan Calculator · 📈 Compound Interest · 🏡 Stamp Duty
The quiet power of a small overpayment
Overpaying a mortgage runs on the same logic as clearing a loan early, only the numbers are larger and the effect more dramatic. Because interest is charged on the outstanding balance, every extra pound you pay stops being charged interest for the whole remaining life of the mortgage. On a typical twenty-five-year term, an extra hundred pounds a month can take years off the end and save a five-figure sum in interest, without your monthly budget changing much.
Two things are worth checking first: whether your lender allows penalty-free overpayments (many cap them at 10% of the balance a year), and whether the money would earn more in a savings account paying a higher rate than your mortgage charges. When the mortgage rate is the higher of the two, overpaying is usually the best guaranteed return you can get.
❓ Frequently Asked Questions
How do I work out how many years are left on my mortgage? ▼
Enter your current balance, interest rate and monthly payment above. The calculator instantly shows how many years and months are left and the date your mortgage will be paid off. You only need those three figures — you can find them on your latest mortgage statement.
When will my mortgage be paid off? ▼
Your payoff date depends on your balance, rate and payment. Enter them above and the calculator gives you the exact month and year — for example "August 2039". If you add a monthly overpayment or a lump sum, it shows how much sooner that date becomes.
How much of my mortgage have I paid off? ▼
Enter your original loan amount in the optional field along with your current balance, and the calculator shows the percentage you've paid off and the amount cleared so far. For example, a £200,000 mortgage now down to £150,000 is 25% paid off (£50,000 cleared).
How can I pay off my mortgage faster? ▼
Overpaying is the most effective way. Because every extra pound goes straight off the balance, you pay interest on a smaller amount for fewer months. Enter a monthly overpayment (or a one-off lump sum) above and the calculator shows exactly how many years sooner you'd be mortgage-free and how much interest you'd save. Always check your lender's annual overpayment limit — most allow up to 10% of the balance per year penalty-free.
How much interest will I save by overpaying? ▼
It's often surprising. On a typical mortgage, overpaying by even £100–£200 a month can save many thousands in interest and shave years off the term. Enter your overpayment above and the green box shows your exact interest saving and how much sooner you'd finish.
How do I pay off my mortgage in 10 years? ▼
Increase the monthly overpayment field until the "Mortgage-free in" figure reads 10 years. The calculator updates live, so you can dial in the exact extra amount per month needed to clear your mortgage in 10 years (or any target), and see the interest it saves.
Is this the same as a mortgage repayment calculator? ▼
Not quite. A repayment calculator is for a new mortgage — you enter the property price and deposit to find the monthly payment. This payoff calculator is for a mortgage you already have — you enter your remaining balance and current payment to find when it'll be cleared and how to finish sooner.
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