Biweekly Mortgage Calculator
This biweekly mortgage calculator shows how much sooner your mortgage could be paid off, and how much interest you could save, if you pay half your monthly payment every two weeks instead of paying once a month. Because there are 26 two-week periods in a year, you end up making the equal of 13 monthly payments rather than 12.
Enter the balance left on your loan, your interest rate (APR) and the number of years left on the loan. The calculator then shows your current monthly payment, the payment every two weeks, the time you would save, the interest you would save and your new payoff time. Check the figures with your lender or bank before making any changes to your payments.
Year-by-year schedule
How to use the biweekly mortgage calculator
- Enter the balance left on your loan in pounds (£) in the first box.
- Enter your interest rate (APR) as a percentage in the second box.
- Enter the number of years left on your loan in the third box.
- Look at your monthly payment now and the payment every two weeks that the calculator works out.
- Compare the time saved, the interest saved and your new time to pay off.
- Ask your lender or bank to confirm the figures and whether biweekly payments are allowed on your loan.
The formula
- Monthly payment = P × r ÷ (1 − (1 + r) ^ −n), where P is the amount borrowed, r the annual rate ÷ 12 ÷ 100 and n the number of months
- Biweekly: half the monthly payment, 26 times a year, with interest at the annual rate ÷ 26 each period (so the loan gets the equal of 13 monthly payments a year)
- Interest saved = interest paying monthly − interest paying every two weeks
Worked example
The figures below are made up to show the maths. They are not current prices, rates or product figures.
| Balance left on the loan | £250,000.00 |
|---|---|
| Interest rate (APR) | 6.5% |
| Years left on the loan | 25 years |
- Time saved 4 years 2 months
- Interest saved £50,391.81
- Payment every two weeks £844.01
- Monthly payment now £1,688.02
- New time to pay off 20 years 10 months
Tips for an accurate answer
- Use the balance from your most recent lender statement so the result reflects what you actually owe.
- Enter the interest rate exactly as it appears on your mortgage terms, as the APR, to get the most accurate result.
- Remember that the calculator works from the figures you enter, so any change in rate or term will change the result.
- Confirm with your lender that they accept fortnightly or biweekly payments and whether there are any fees for doing so.
- Use the result as an estimate of the maths, not as financial advice, and check it with your lender before you decide.
Questions people ask
How fast will I pay off my mortgage with biweekly payments?
Enter your balance, interest rate (APR) and years left, and the calculator shows your new time to pay off. In the worked example, a £250,000.00 balance at 6.5% over 25 years gives a new payoff time of 20 years 10 months, which is 4 years 2 months sooner. Your own result will depend on the figures you enter.
How many years does a biweekly mortgage save?
The calculator shows the time saved by comparing your current term with the new payoff time for biweekly payments. In the worked example, the time saved is 4 years 2 months on a £250,000.00 balance at 6.5% with 25 years left.
Can I use this biweekly mortgage calculator if I also make extra payments?
This calculator only compares paying half your monthly payment every two weeks with paying monthly. It does not include extra lump-sum payments, so ask your lender how extra payments would affect your balance.
How do I use a bi weekly mortgage calculator in the UK?
Enter your balance left on the loan in pounds, your interest rate (APR) as a percentage, and the years left on the loan. The calculator then shows your payment every two weeks, your current monthly payment, and the time and interest you could save.
What does the biweekly mortgage calculator actually work out?
It works out how much sooner your mortgage would be paid off, and how much interest you would save, if you pay half your monthly payment every two weeks. It also shows the payment every two weeks and your current monthly payment for comparison.
Why does paying every two weeks reduce the time to pay off?
Paying every two weeks means 26 half-payments a year, which equals 13 monthly payments rather than 12. That extra payment each year goes towards the balance, so less interest builds up and the loan clears sooner.
What figures do I need to enter?
You need the balance left on your loan, your interest rate (APR) as a percentage, and the number of years left on the loan. These three figures are all the calculator needs to compare the two payment schedules.
Is the result exact?
The result is a mathematical estimate based on the figures you enter and the formula used by the calculator. Your lender may calculate interest and payments differently, so confirm the figures with them.
Sources
This calculator uses the standard loan and interest formulas above and the numbers you type. It needs no outside figures.
An estimate from the numbers you enter, worked out with the formula shown. It is maths, not financial advice: your lender or bank has the final figures. Page checked 23 Oct 2026. Read the disclaimer