Biweekly Mortgage Calculator

Inputs

Biweekly flow uses half the monthly payment every two weeks plus any extra. Interest accrues biweekly for the simulation.

Results

Monthly payment $1,798.65
Biweekly base (half of monthly) $899.33
Biweekly payment (incl. extra) $899.33

Total interest (monthly) $347,514.57
Total interest (biweekly) $273,078.55
Interest saved $74,436.02

Payoff date (monthly): 2056-01-25

Payoff date (biweekly): 2050-07-10

Estimated time saved (days): 2,025

Payments in year (biweekly): 26

Example Data

Inputs

Loan amount	300,000.00
APR (annual %)	6.000
Term (years)	30
Start date	2026-01-25
Extra biweekly	0.00

Outputs

Monthly payment	1,798.65
Biweekly base	899.33
Payments per year (biweekly)	26

Use your own numbers in the form to generate a personalized schedule and updated chart.

Formulas Used

Monthly payment (amortization):
  P_m = L * r_m / (1 - (1 + r_m)^(-N_m))
  where L = loan amount, r_m = annual_rate/12, N_m = term_years*12

Biweekly simulation (industry approach):
  Pay half the monthly amount every 14 days (26 half-payments per year).
  Interest each biweekly period:
    I_b = B * r_b,  r_b = annual_rate/26
  Principal paid = Payment_biweekly - I_b
  New balance = B - Principal paid

Note:
  Many lenders credit biweekly payments as they arrive, which accelerates payoff.
  This tool simulates that flow. Results approximate everyday practice.

How to Use This Calculator

Enter your loan amount, annual rate, term in years, and start date.
Optionally add an extra amount to each biweekly payment to speed payoff.
Press Calculate to view payments, payoff dates, and total interest.
Scroll to see the amortization chart and compare monthly versus biweekly trends.
Export your schedule to CSV or save a PDF of the results section.

FAQs

1) What is a biweekly mortgage?
It splits your monthly payment into two equal parts paid every two weeks. You make 26 half-payments per year, roughly equal to 13 monthly payments.

2) Why does biweekly reduce interest?
Because your balance is reduced more frequently and you effectively pay an extra monthly equivalent each year, the loan term shortens and interest declines.

3) Are the payments exactly half of monthly?
Yes for this calculator’s schedule. We base each biweekly payment on half the standard monthly payment plus any extra you specify.

4) Do lenders calculate interest daily or monthly?
Practices vary. This tool uses a biweekly interest step for clarity, which closely mirrors typical outcomes for practical comparisons.

5) What if my rate changes?
This model assumes a fixed rate. For adjustable loans, re-run the calculation when terms reset or use piecewise periods.

6) Can I add a one-time lump sum?
Enter it as a large extra amount temporarily and run the calculation for that period, or export CSV and adjust outside the tool.

7) Why is my payoff date different from my lender’s?
Minor differences in accrual conventions, posting dates, and rounding can shift outcomes. Treat this as a precise planning estimate.

Inputs

Results

Example Data

Inputs

Outputs

Formulas Used

How to Use This Calculator

FAQs

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