Mortgage Estimates

Mortgage Amortization Calculator

Amortization inputs

Monthly and bi-weekly comparison

Compare monthly payments with accelerated bi-weekly payments that use half the monthly principal and interest amount every 14 days.

Monthly Bi-Weekly
Payment Per Period $— $—
Total Interest Paid $— $—
Total Payments — —
Payoff Date — —
Full monthly amortization schedule
Month by month principal, interest, and balance
Month Payment Principal Interest Balance

Monthly schedule is standard fixed-rate amortization. Bi-weekly compares paying half your monthly P&I every 14 days, with interest accrued on ACT/365. Payoff assumes the loan begins today (local date). Taxes, insurance, extra payments, lender rounding, and true bi-weekly products may differ.

How the Mortgage Amortization Calculator Works

An amortization calculator shows how each payment splits between principal and interest over time, and how the outstanding balance declines on a fixed-rate schedule. This version also contrasts a traditional monthly payment plan with an accelerated bi-weekly approach—paying half of the monthly P&I every two weeks—so you can see potential interest savings and an earlier payoff date in one view.

Enter your loan amount, nominal annual interest rate, and term, then run Calculate. You will get a comparison table for payment per period, total interest, number of payments, and payoff timing, plus an expandable month-by-month schedule that lists payment, principal, interest, and remaining balance for each month of the loan.

You will need:

  • Principal or loan balance being amortized
  • Stated annual interest rate on the note
  • Repayment term in years (15, 20, or 30)

Use the detailed schedule to understand front-loaded interest, to verify payoff targets, or to discuss extra-payment strategies with a loan officer. Remember that escrow, mortgage insurance, and lender-specific rounding can change real-world numbers; this schedule focuses on standard fixed-rate principal and interest mathematics.

Frequently asked questions

What is the difference between monthly and bi-weekly here?

Monthly follows a standard fixed-rate payment every month. Bi-weekly assumes you pay half of that monthly P&I every 14 days, which yields extra principal over a year and can shorten the loan.

Why might my lender’s schedule differ slightly?

Lenders may round payments or balances differently, use a slightly different day-count or first-payment date, or apply fees and escrow separately. This tool models standard P&I amortization for education, not a specific servicing system.

What does ACT/365 mean for the bi-weekly column?

Interest accrual for the bi-weekly path uses an actual-days-in-year convention (365), as noted in the disclaimer, rather than a simplified 30/360 schedule. That can produce small differences versus other calculators.

Can I model extra payments or lump-sum paydowns?

Not in this version. The month-by-month grid is a straight amortization with no optional add-ons. You can note side effects with your lender or use the schedule as a baseline and adjust manually.

How is the payoff date determined?

The summary assumes the loan starts today using your local date, then walks forward by payment count. Holidays, funding delays, and true bi-weekly program rules are not applied.