Bi Weekly Mortgage Payments Calculator
Paying half your mortgage every two weeks adds up to 13 monthly payments a year instead of 12, and that extra payment goes straight at the principal. This calculator simulates both schedules payment by payment, so you see the exact interest saved, the years shaved off, and a year-by-year balance comparison. Our standard monthly payment calculator answers the plain monthly question; this page owns the biweekly question.
Biweekly periods use a periodic rate of APR ÷ 26. The final payment is trimmed so the balance lands exactly on zero. Open the “Balance year by year” tab to watch the two schedules diverge.
Remaining balance at the end of each year, monthly schedule versus biweekly schedule. Biweekly years are 26-payment blocks, which run very close to calendar years.
| Year | Monthly schedule balance | Biweekly schedule balance |
|---|---|---|
| Click Calculate on the Calculator tab to build this table. | ||
Quick Answer
On a $350,000 mortgage at 6.8% APR over 30 years, paying half the monthly payment every two weeks saves $113,268.65 in interest and pays the loan off 6 years 1 month early (621 payments instead of 360). The whole trick is the 13th payment: 26 half-payments a year equal 13 monthly payments, and that extra payment attacks principal every year.
Key takeaways
- Biweekly payments are simply half the standard monthly payment paid every 14 days, giving 26 half-payments (13 full payments) a year instead of 12.
- The calculator simulates both schedules payment by payment, so every figure, including the year-by-year balances, comes from real amortization math, not a shortcut formula.
- The DIY alternative costs nothing: add one-twelfth of your monthly payment ($190.14 in the example) to each monthly payment, marked as principal.
- Bank biweekly programs can charge setup or per-payment fees, and some servicers hold the first half-payment without applying it. The DIY method avoids both traps.
- Quick Answer
- How to use this biweekly calculator
- The 13th-payment math, step by step
- Worked example: $350,000 at 6.8% APR
- Bank biweekly program or the DIY monthly add-on?
- What competing biweekly calculators miss
- Three catches worth knowing before you switch
- Frequently asked questions
- Add This Calculator to Your Website
- References
How to use this biweekly calculator
Enter five numbers and read the comparison. The results stay hidden until you click Calculate, and every input is pre-filled with the worked example below.
- Enter the loan amount: your current principal balance, for example 350000. It must be greater than zero.
- Enter the annual interest rate: the fixed APR as a percent, for example 6.8. Zero is allowed for interest-free loans.
- Enter the loan term: the remaining years, for example 30. This sets the monthly baseline the biweekly schedule is compared against.
- Add the optional fields: a first payment date if you want a calendar payoff date, and an extra amount per biweekly payment if you want to model paying more.
- Click Calculate: the tool shows both schedules, the savings, the DIY equivalent, and a verdict sentence. Open the Balance year by year tab to watch the two balances diverge.
Invalid inputs are rejected with plain messages: a blank or non-positive loan amount (“Please enter a valid loan amount.”), a missing or negative rate (“Please enter a valid interest rate (0 or more).”), a missing or non-positive term (“Please enter a valid loan term in years.”), and a negative extra payment (“Extra payment cannot be negative.”).
The 13th-payment math, step by step
Biweekly payments have no secret formula: the standard amortized monthly payment is computed first, halved, and then both schedules are simulated one payment at a time. That simulation is what makes the results exact.
Biweekly payment = monthly payment ÷ 2, then each of the 26 annual payments accrues interest at APR ÷ 26 before reducing principal.
Extra principal per year = biweekly payment × 26 − monthly payment × 12, which equals one full monthly payment plus 26 times any extra amount you add.
Each simulated period works the same way: the interest for that period is the current balance times the periodic rate, and the rest of the payment reduces the principal. The final payment is trimmed so the balance lands exactly on zero. Because the biweekly schedule pays half the monthly amount every 14 days, 26 payments land each year instead of 12, which is the 13th payment. That payment goes entirely to principal, which is why it compounds so powerfully: next year every payment carries a little less interest.
One honest convention to state: this tool uses a periodic rate of APR ÷ 26 for the biweekly schedule. Some lenders use APR ÷ 365 × 14, which differs by a few dollars per period. The savings picture is unchanged either way, but if your servicer uses the daily convention your numbers may differ by small amounts from what you see here.
Worked example: $350,000 at 6.8% APR
A $350,000 mortgage at 6.8% APR over 30 years is pre-filled in the calculator. The standard monthly payment comes out at $2,281.74, so the biweekly payment is $1,140.87 every two weeks. Here is what the simulation produces:
- Monthly schedule: $471,425.74 total interest over 30 years (360 payments)
- Biweekly schedule: 621 payments over 23 years 11 months, $358,157.08 total interest
- Interest saved: $113,268.65; time saved: 6 years 1 month
- Extra principal per year: $2,281.74, exactly one monthly payment, which is the 13th payment
- DIY equivalent: add $190.14 (one-twelfth of $2,281.74) to each monthly payment, marked as principal
- Balance after 5 years: $328,746.56 monthly versus $315,141.34 biweekly
- Balance after 10 years: $298,915.24 monthly versus $266,188.47 biweekly
- Balance after 23 years: $152,165.59 monthly versus $25,130.30 biweekly
Type these same figures into the calculator and every number above reappears exactly. The chart below scales the two lifetime-interest totals so you can see the gap at a glance.
Total lifetime interest, same loan
The biweekly schedule pays 24% less interest, a gap of $113,268.65, for the same loan terms.
Bank biweekly program or the DIY monthly add-on?
The DIY method wins for most borrowers because it costs nothing and produces nearly identical savings. Both approaches make the same extra annual payment; only the delivery differs.
Bank biweekly program
The servicer drafts half your payment every two weeks. Setup or per-payment fees are common, and some servicers hold the first half-payment in a suspense account until the second arrives, which erases part of the benefit. The CFPB has taken enforcement action against third-party biweekly payment companies for exactly these practices.
Best for: borrowers who want the schedule enforced automatically and trust their servicer to apply payments immediately at no charge.
DIY monthly add-on
Add one-twelfth of your monthly payment to each monthly payment and mark it as additional principal. On the $350,000 example that is $190.14 a month. The yearly total matches the biweekly 13th payment exactly, there are no fees, and you keep full control. The one requirement: confirm with your servicer that extra amounts reduce principal rather than advancing the due date.
Best for: almost everyone, especially borrowers whose servicer charges biweekly fees or holds half-payments.
If you get paid every two weeks, the budgeting angle matters too: two months a year bring a third paycheck, and a biweekly budget calculator helps you aim those windfalls at the principal instead of spending them.
What competing biweekly calculators miss
Biweekly mortgage tools cluster into camps, and each leaves something out:
- Payment-only tools: they show the biweekly amount and stop, giving no payoff date, no total-interest comparison, and no year-by-year view. You learn the payment, not the payoff.
- Savings-only tools: they headline the interest saved but never explain the DIY alternative, leaving you to assume you need a bank program with fees to get it.
- Rate-convention silence: most tools never state whether they use APR ÷ 26 or a daily-rate convention, so you cannot tell why your servicer’s figure differs by a few dollars. This page states its convention openly.
- No balance timeline: few tools put the monthly and biweekly balances side by side year by year, so the moment the gap becomes dramatic stays invisible. In the example above, by year 10 the biweekly balance is already $32,727 lower, and by year 23 the biweekly loan is nearly gone while the monthly one still owes $152,165.59.
- The gap this page fills: both schedules simulated payment by payment, the stated rate convention, the year-by-year balance table in its own tab, the exact DIY monthly add-on for every result, and the fee warnings most tools skip.
Three catches worth knowing before you switch
Biweekly payments are genuinely powerful, but three details trip borrowers up.
- Servicer application rules vary. Some servicers apply each half-payment immediately; others hold the first half until the second arrives, which turns the schedule into plain monthly payments with extra paperwork. Ask in writing how half-payments are applied before you start.
- Fees can eat the savings. Setup fees and per-payment charges are common on bank-run biweekly programs. The CFPB’s 2015 enforcement action against a biweekly payment company documented transaction fees on every withdrawal and enrollment fees collected before any extra payment reached the loan. The DIY add-on has no fees at all.
- Check the rate first. If your rate is well above current market rates, refinancing may beat a biweekly schedule on total savings. Run the cost to refinance numbers before committing to years of extra payments on an expensive loan.
One more honest limit: this calculator assumes a fixed rate and that extra amounts reduce principal. It does not model adjustable-rate loans, taxes, insurance, or PMI.
Frequently asked questions
Almost all of the savings come from the extra annual payment. Twenty-six half-payments equal 13 monthly payments, and that 13th payment goes entirely to principal each year, which shrinks the balance that future interest is charged on. On the $350,000 example above, that mechanism alone saves $113,268.65.
No. Add one-twelfth of your monthly payment to each monthly payment and mark it as additional principal. On the worked example that is $190.14 a month. Confirm with your servicer that extra amounts reduce principal rather than advancing the due date.
Some servicers charge setup or per-payment fees for biweekly programs, and some hold the first half-payment without applying it until the second arrives, which erases part of the benefit. Third-party biweekly companies have been penalized by the CFPB for exactly these practices. The DIY monthly add-on avoids both problems.
Yes, but differently. There is no interest to save, yet the extra annual payment still shortens the term. On a $300,000 loan at 0% over 30 years, the biweekly schedule pays off in 27 years 8 months instead of 30.
They are nearly identical in total savings. Biweekly spreads the extra across the year, so each piece starts reducing interest slightly sooner, which gives biweekly a small timing edge, usually measured in weeks on a 30-year loan.
A biweekly year is 26 payments of 14 days, which is 364 days, one or two days short of a calendar year. The balance table labels each 26-payment block as a year for readability. Over a 30-year loan the drift is only a few weeks and does not change the savings picture.
On-time biweekly payments help your credit the same as monthly ones. Your mortgage interest deduction shrinks over time because you pay less interest, which is the good kind of shrinking: IRS Publication 936 covers how the deduction works on whatever interest you actually pay.
Add This Calculator to Your Website
Embed this calculator on your own site with the code below. Pick a size to preview it live, then copy the code.
Powered by Calculator Zilo
References
- Freddie Mac. Is There a Faster Way to Be Mortgage-Free? (biweekly payments produce 13 full payments a year; extra principal shortens the loan). Accessed October 24, 2026.
- Internal Revenue Service. Publication 936, Home Mortgage Interest Deduction (what interest is deductible and how limits apply). Accessed October 24, 2026.
- Consumer Financial Protection Bureau. Consent Order, 2015-CFPB-0017 (enforcement against a biweekly payment company: transaction fees on every withdrawal, enrollment fees collected before extra payments reached the loan). Accessed October 24, 2026.
- Mortgage Professor (Jack Guttentag, Wharton emeritus). Will a Weekly, Bimonthly or Biweekly Payment Mortgage Really Save Me Money? (biweekly mechanics; raising every monthly payment by 1/12 matches the biweekly payoff almost exactly). Accessed October 24, 2026.
- Nasdaq (syndicated guide). Should You Make Biweekly Mortgage Payments? (26 half-payments equal 13 full payments; pros and cons under the right and wrong circumstances). Accessed October 24, 2026.