Biweekly Mortgage Payment Calculator
See how paying half your mortgage payment every two weeks (26 payments a year) shortens your loan and slashes total interest.
How to use this tool
- Enter your remaining loan amount, interest rate, and original term.
- The calculator finds your standard monthly payment and halves it for the biweekly amount.
- Read your accelerated payoff time and the total interest you would save versus monthly payments.
Paying your mortgage biweekly squeezes in one extra monthly payment each year without a big budget change. Enter your loan to see the biweekly amount, the new payoff date, and the interest you would save.
Formula
Monthly payment M = P · r / (1 − (1 + r)−n), where r = APR ÷ 12 and n = years × 12.
Biweekly payment = M ÷ 2, charged every two weeks (26 times a year, so you make the equivalent of 13 monthly payments annually instead of 12).
Payoff time = −ln(1 − P · rbw ÷ biweekly) ÷ ln(1 + rbw) biweekly periods, where rbw = APR ÷ 26. Interest saved is the monthly-plan total interest minus the biweekly-plan total interest.
How it works
A biweekly mortgage plan splits your normal monthly payment in half and charges it every two weeks. Because a year has 52 weeks, that is 26 half-payments — the equivalent of 13 full monthly payments instead of 12. The extra payment goes straight to principal, so the balance falls faster and less interest accrues over the life of the loan.
The calculator first derives your standard amortized monthly payment, halves it, then solves the closed-form number of biweekly periods needed to reach a zero balance at a per-period rate of APR ÷ 26. Interest saved is the difference between total interest on the ordinary monthly schedule and the biweekly schedule. We assume the lender applies each biweekly payment when received and charges no extra fees; some servicers instead hold payments and remit monthly, which removes the benefit, so confirm how your servicer handles biweekly payments.
Reviewed by the AbraCalc Mortgage Desk. This is an educational estimate, not financial advice; your actual savings depend on your servicer's accrual and posting rules.
Worked example
$200,000 at 6% over 30 years
- Monthly rate r = 6% ÷ 12 = 0.005; n = 30 × 12 = 360.
- Monthly payment = 200,000 × 0.005 ÷ (1 − 1.005^−360) = $1,199.10.
- Biweekly payment = 1,199.10 ÷ 2 = $599.55.
- Biweekly rate = 6% ÷ 26 = 0.0023077; periods = −ln(1 − 200,000 × 0.0023077 ÷ 599.55) ÷ ln(1.0023077) ≈ 637.3, or 24.51 years.
- Monthly-plan interest = 1,199.10 × 360 − 200,000 = $231,676; biweekly-plan interest ≈ $182,052; saved ≈ $49,624.14.
Biweekly payment = $599.55, payoff in 24.51 years, interest saved ≈ $49,624.14
Biweekly payoff and interest saved (30-year loans)
| Loan | Rate | Biweekly payment | Payoff time | Interest saved |
|---|---|---|---|---|
| $150,000 | 6% | $449.66 | 24.5 yrs | $37,218 |
| $200,000 | 6% | $599.55 | 24.5 yrs | $49,624 |
| $300,000 | 5% | $805.23 | 25.2 yrs | $51,492 |
| $400,000 | 7% | $1,330.60 | 23.7 yrs | $137,851 |
Key terms
- Biweekly payment
- Half of your monthly payment, paid every two weeks — 26 times per year.
- Amortization
- The schedule by which each payment is split between interest and principal until the loan is paid off.
- Principal
- The outstanding loan balance on which interest is charged.
- Effective 13th payment
- Because 26 half-payments equal 13 full payments, biweekly plans add one extra monthly payment per year toward principal.
Frequently asked questions
- How does paying biweekly save money?
- Twenty-six half-payments equal 13 full monthly payments a year instead of 12. That extra payment reduces principal directly, so less interest accrues and the loan ends years earlier.
- Is a biweekly plan the same as paying extra monthly?
- Roughly. Adding 1/12 of a payment to each monthly payment achieves a similar result. Biweekly plans automate the equivalent of one extra payment per year; the small difference comes from paying every two weeks rather than monthly.
- Will my lender charge for biweekly payments?
- Some servicers charge enrollment or per-payment fees, and some hold biweekly payments and apply them monthly, which erases the benefit. Confirm that payments are applied as received before enrolling.