Biweekly Mortgage Payment Calculator
Pay half your mortgage every two weeks instead of the full payment monthly. Twenty-six half-payments = thirteen full payments a year, and your loan ends years early.
About this tool
A biweekly mortgage calculator that shows the real impact of switching payment frequency. Most mortgages bill monthly (12 payments / year). A biweekly schedule produces 26 half-payments — the equivalent of 13 full payments. That single extra payment per year, applied over a 30-year mortgage, knocks 4–6 years off the loan and saves five-figure interest.
How to use it
Quick steps to get the most out of this utility.
- 1
Enter your mortgage details
Loan amount, interest rate, and remaining term. Use the current balance if you have already been paying for a while.
- 2
Compute the biweekly amount
Your biweekly payment is exactly half of your monthly. The math handles the rest.
- 3
Run the comparison
See total interest, payoff date, and final-year balance for both monthly and biweekly schedules.
- 4
Check your lender's rules
Some lenders apply biweekly halves to principal immediately (best); others hold them until a full monthly equivalent is reached. The savings differ — verify before switching.
- 5
Export & confirm
Download the schedule, then ask your lender to set up a true biweekly plan with no third-party "biweekly service" fees.
The calendar trick behind biweekly savings
A year has 52 weeks. Pay every 14 days and you make 52 ÷ 2 = 26 payments. Half of your monthly amount × 26 = 13 monthly equivalents. The 13th payment, every single year, goes entirely to principal. Compounded over 30 years, that single quirk of the calendar is worth tens of thousands of dollars.
A worked example
On a $400,000 mortgage at 7% over 30 years:
- Monthly payment: ~$2,661. Total interest over 30 years: ~$558k.
- Biweekly half-payment: ~$1,330 every 14 days. Loan paid off in ~24 years. Total interest: ~$466k.
- Net savings: ~$92k in interest and ~6 years of mortgage payments.
Three ways to capture the same savings
- True biweekly via your lender (free if available, best savings, requires lender support).
- Monthly + 1/12 extra principal each month (DIY, near-identical savings, full flexibility).
- One extra full monthly payment per year as a year-end lump sum (simplest, slightly less savings, easy to time with a bonus).
Frequently asked questions
How does a biweekly schedule save so much interest?+
You make 26 half-payments a year instead of 12 full ones — that is 13 full monthly equivalents, not 12. The extra month per year is applied entirely to principal, which compounds against the remaining balance and shortens the loan dramatically. On a 30-year $400k mortgage at 7%, biweekly typically saves $90k+ in interest and ends the loan ~6 years early.
Is biweekly the same as "paying half twice a month"?+
No, and the difference is critical. "Twice a month" = 24 payments a year = same as 12 monthly. "Every two weeks" = 26 payments a year = the equivalent of 13 monthly. Calendars produce two months a year with three biweekly periods, and that is where the extra month of principal reduction comes from. If your lender splits payments "semi-monthly," you get zero benefit.
Should I pay a biweekly service company to set this up?+
No. Third-party services typically charge a $300–500 setup fee plus $5–10 per payment. They are not doing anything you cannot do directly with your lender — and many lenders now offer true biweekly setup for free. If your lender refuses, just add 1/12 of your monthly payment to each monthly payment as principal — it produces almost identical savings without the fee or the contract.
Are there any downsides to biweekly payments?+
Three to consider. (1) Cashflow — you are committing to one extra month of mortgage per year, so the household budget needs that slack. (2) Opportunity cost — the same extra month invested at 8%+ over 30 years can outperform mortgage interest savings, especially in a tax-advantaged account. (3) Lender lock-in — once set up, some lenders make it hard to revert. Read the agreement first.
Biweekly vs just prepaying $X every month — which is better?+
Mathematically nearly identical, with one wrinkle. A formal biweekly schedule applies a half-payment every two weeks, so the principal drops 14 days earlier each cycle than a single monthly extra payment would. Over 30 years that timing advantage adds another ~6 months of savings versus the same dollar amount paid as a monthly extra. The simplicity of "just add $X monthly" usually wins for most households, though.
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