Biweekly Mortgage Calculator
A true biweekly simulation — a half-payment every 14 days with daily interest accrual — showing exact years shaved, interest saved, payoff date, and whether investing the difference beats it.
- 30yr Fixed6.51%
- 15yr Fixed5.84%
- 5/1 ARM6.47%
- 2yr Fixed5.68%
- 5yr Fixed5.63%
- Tracker3.96%
- Variable6.20%
- 2yr Fixed5.90%
- 5yr Fixed5.54%
- Variable5.95%
Rates shown are national averages for reference only. Actual rates vary by lender, credit score, and LTV. US 30/15-yr figures auto-refresh daily from the Freddie Mac PMMS public dataset.
Inputs
How it works
Standard schedule: monthly P&I amortization at your rate for the full term.
Biweekly schedule: a payment of half the monthly P&I (plus optional extra) every 14 days, with daily interest accrual at rate/365 between payments. That produces 26 payments per year instead of 24 — one extra full payment straight to principal.
Opportunity cost: the ~1 extra payment/year equals about monthly/12 per month. We invest that same cash flow at your assumed return and compare growth against the interest saved.
Frequently asked questions
How does biweekly actually work?
You pay half your monthly amount every 14 days. Since a year has 26 fortnights (not 24), you make 26 half-payments = 13 full payments per year — one extra applied directly to principal.
Is this a real biweekly simulation?
Yes. We accrue daily interest at rate/365 between each 14-day payment and apply the payment on that exact day — not the '1/12 extra per month' approximation many calculators use.
Do all lenders support biweekly?
Most do, but some charge a setup fee ($200–$400) or hold funds until a full monthly payment accumulates. Read the fine print, or DIY by adding 1/12 of your payment as extra principal each month.
Should I choose biweekly or just invest the difference?
Compare your after-tax mortgage rate to your expected after-tax investment return. The verdict box above runs that math on your inputs.
Does biweekly affect my credit or taxes?
No credit impact. Mortgage interest is still deductible if you itemize — you'll just have less of it to deduct.