Biweekly Mortgage Calculator: Savings vs Monthly
A biweekly plan is a specific strategy: half your monthly payment every two weeks, which adds up to one extra payment a year. Enter your loan to see how long it takes off the term and how much interest it saves.
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Formula
- Monthly payment:
M = P × r × (1 + r)^n ÷ ((1 + r)^n - 1)withrthe monthly rate andnthe months. - Biweekly payment:
M ÷ 2, paid 26 times a year. - Each two weeks interest is
balance × annual rate ÷ 26; the payment is subtracted, and the loop runs until the balance is zero. - Interest saved is the monthly plan's total interest minus the biweekly plan's total interest.
Worked example
A loan of 300,000 at 6% over 30 years:
- Monthly payment
M = 1,798.65, total interest347,514.57. - Biweekly payment
899.33. It is paid off after 638 payments, which is 24.5 years. - Total interest is
273,078.55, so you save 74,436.02 and about 5.5 years.
When to use it
Use this page when your lender or employer offers a biweekly schedule and you want to know if it pays. If you can make any extra payment on your own terms, the extra mortgage payment calculator gives you more control over amount and timing. The mortgage payoff calculator is for when the payment is already fixed.
Second example
A loan of 400,000 at 7% over 30 years has a monthly payment of 2,661.21. Paying 1,330.60 every two weeks ends the loan in 23.7 years, saving 6.3 years and 137,850.57 of interest.
Common mistakes
- Joining a paid third-party program when you could send one extra payment yourself at no cost.
- Assuming the lender applies each half-payment immediately; some hold it until the monthly date and the saving disappears.
- Mixing semi-monthly (24 payments) with biweekly (26).
Frequently asked questions
How does a biweekly mortgage save money?
There are 52 weeks, so 26 biweekly half-payments, which equal 13 monthly payments instead of 12. The extra half of a payment each year goes to the balance. On 300,000 at 6% over 30 years it pays off in about 24.5 years and saves about 74,436 in interest.
How is the biweekly payment worked out?
It is half the monthly payment. For 300,000 at 6% over 30 years the monthly payment is 1,798.65, so the biweekly payment is 899.33 paid 26 times a year.
How does the calculator charge interest?
It charges the yearly rate divided by 26 on the balance each two weeks. Some lenders only apply a payment on the monthly date, which removes most of the saving, so check how yours handles it.
Can I get the same result without a biweekly plan?
Yes. Paying one extra monthly payment a year, or adding one twelfth of the payment to every month, gives a similar result with no fees. Some biweekly programs charge a setup or transaction fee, which this page does not include.
Is a biweekly mortgage worth it?
It saves interest only because it adds one extra payment each year. On 200,000 at 5% over 30 years it saves 34,327.94 of interest and 4.7 years. If your lender charges setup or per-payment fees, compare the saving with those costs.
Biweekly vs one extra payment a year: which is better?
They are close. On 300,000 at 6% the biweekly plan saves 74,436 and 5.5 years, while one extra monthly payment of 1,798.65 each year saves about 76,438 and 5.6 years in the extra payment calculator, because it is made at the start of each year.
What is the difference between biweekly and semi-monthly payments?
Biweekly means every two weeks, 26 payments a year. Semi-monthly means twice a month, 24 payments a year, which equals 12 full payments and saves nothing. Only the 26-payment schedule produces the extra payment.