Bi-weekly Mortgage Calculator
See how much paying half your mortgage payment every two weeks saves. Twenty-six half-payments a year add up to one extra monthly payment, and this calculator shows how much sooner the loan ends and how much interest that saves.
How to Use
- Enter the loan balance (the original amount for a new loan), the interest rate and the years left to pay.
- Pick the month of the first payment so the payoff dates match your calendar.
- If a company charges you to run a bi-weekly plan, enter its set-up fee and the fee per debit; leave both at 0 if you pay your lender directly.
- Read the interest saved, the time saved and the new payoff date, then compare the five ways of paying in the table under the chart.
- Open the schedule to see every bi-weekly payment, by year or one by one, or download it as a CSV file.
Worked Example
$300,000 at 6.5% for 30 years. The monthly payment is M = 300,000 × 0.00541667 × 1.00541667³⁶⁰ ÷ (1.00541667³⁶⁰ − 1) = $1,896.20, and over 360 payments the interest comes to $382,633.47. Paying half of it, $948.10, every 14 days means 26 half-payments a year — 13 monthly payments instead of 12. With interest charged at 6.5% ÷ 26 = 0.25% per period, the first payment is $750.00 interest and $198.10 principal, and the loan is gone after 628 payments (24.2 years). Interest falls to $294,511.68, a saving of $88,121.78, and the loan ends 5 years 10 months early.
The same thing, monthly. One extra payment a year is $1,896.20 ÷ 12 = $158.02 a month. Paying $2,054.22 every month ends the loan after 290 payments and saves $87,256.29 — within 1% of true bi-weekly, with no new payment schedule.
The common mistake: thinking the saving comes from paying more often. Split the same $22,754.45 a year into 26 payments of $875.17 and the loan takes 779 payments and saves just $991.39, not $88,121.78. The saving comes from the 13th payment. A program that holds your half-payments and sends the surplus once a year still saves $83,984.52, because the extra money still reaches the loan.
Show Work
Formulas
Why 26 Half-Payments Make 13
Monthly payments follow the calendar: twelve a year. A two-week cycle follows the week: 52 weeks ÷ 2 = 26 payments, and 26 halves are 13 whole payments. Because 26 × 14 = 364 days, the cycle also drifts 1¼ days a year against the calendar (365¼ days), so roughly every 11 years a calendar year holds 27 bi-weekly dates instead of 26. That drift is why bi-weekly schedules carry exact dates rather than “the 1st of the month”, and why this calculator’s schedule lists days.
The name covers two different arrangements. In a true bi-weekly loan the lender applies each half-payment when it arrives, so the balance falls every 14 days. Some third-party plans instead collect every two weeks, hold the money, pay your lender once a month, and pass the surplus on later — the loan then gains only when the surplus arrives. Canadian lenders use “accelerated bi-weekly” for the half-monthly-payment version, to tell it apart from 26 payments that only add up to the usual twelve. This calculator shows all of them side by side, along with the simplest route of all: 1/12 of a payment extra each month.
About This Tool
This calculator compares a fixed-rate loan paid monthly with the same loan paid half the monthly amount every 14 days. It reports the interest saved, how much sooner the loan ends and the new payoff date, draws both balances falling over time, and lists the full bi-weekly schedule with dates, by year or by payment, with a CSV download. The comparison table adds the monthly equivalent (1/12 extra each month), a program that sends the surplus once a year, and 26 payments that add up to only twelve, so you can see where the saving really comes from. Interest on the bi-weekly loan is the yearly rate ÷ 26 per period; lenders that charge daily interest will differ by a few dollars.
Everything runs in your browser; nothing you enter is sent anywhere. For a loan you are paying down with other extra amounts, the Mortgage Payoff Calculator takes any extra payment or lump sum.
Estimates for planning and education — not financial, tax or legal advice.
Related tools: Mortgage Calculator, Amortization Calculator, and Refinance Calculator.
Frequently Asked Questions
Why does paying every two weeks save so much?
A year has 52 weeks, so paying half the monthly payment every two weeks means 26 half-payments — the same as 13 monthly payments instead of 12. On $300,000 at 6.5% for 30 years the monthly payment is $1,896.20; paying $948.10 every two weeks ends the loan after 628 payments (about 24.2 years) and saves $88,121.78 of interest.
Is a bi-weekly payment the same as one extra payment a year?
Very nearly. Adding 1/12 of the payment each month — $2,054.22 instead of $1,896.20 on the $300,000, 6.5% loan — pays it off after 290 months and saves $87,256.29. True bi-weekly saves $88,121.78 because each half-payment reaches the balance a little earlier. The extra money, not the timing, does almost all the work.
What if I split my yearly payments into 26 smaller ones?
Then you pay no extra money and save almost nothing. Paying $1,896.20 × 12 ÷ 26 = $875.17 every two weeks on the same loan takes 779 payments and saves only $991.39. Lenders sometimes call this plain “bi-weekly”; the version that saves money pays half the monthly payment.
What if a program collects every two weeks but pays my lender monthly?
Then your loan is still charged interest monthly, and you gain only when the surplus is passed on. If the program sends the extra $1,896.20 once a year, the $300,000, 6.5% loan ends after 292 payments and saves $83,984.52 — less than true bi-weekly’s $88,121.78. Ask your servicer when each payment is applied.
Are bi-weekly program fees worth paying?
Usually you can get the same result free by adding 1/12 of a payment each month. If a program charged a $300 set-up fee and $2.50 per debit, the 628 debits on the $300,000, 6.5% loan would cost $1,870, cutting the saving from $88,121.78 to $86,251.78. Check first that your lender accepts extra principal without a fee.
How do I use the Bi-weekly Mortgage Calculator?
Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.
Do I need to install or sign up for anything?
Not at all — it runs in the browser with nothing to install and no account. After it loads once, it even works without an internet connection.
Is my information private?
Yes. Everything happens in your browser. Nothing you type is sent to a server or saved anywhere.
Common Use Cases
Matching paydays
If you are paid every two weeks, paying $948.10 from each paycheck instead of $1,896.20 once a month ends a $300,000, 6.5% loan 5 years 10 months early.
A larger loan
On $450,000 at 7% for 30 years the bi-weekly payment is $1,496.93, and it saves $155,081.89 of interest and 6 years 3 months.
A 15-year loan
Even on $250,000 at 6% for 15 years, half-payments every two weeks save $17,427.08 and finish 1 year 9 months sooner.
Part-way through a loan
With $200,000 left at 6.5% and 20 years to go, switching to $745.57 every two weeks saves $26,260.10 and 2 years 11 months.
Checking a program’s fees
A $300 set-up fee plus $2.50 a debit costs $1,870 over 628 payments — compare it with adding $158.02 a month yourself.
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