Bi-Weekly Mortgage Calculator — See How Much You Save with Extra Payments
Paying half your mortgage every 14 days lands 26 payments a year — the equivalent of 13 monthly payments instead of 12. That thirteenth payment is an extra payment straight to principal: on a $300,000 loan at 7%, it saves $103,388 in interest and clears the loan 6 years, 3 months early. Bi-monthly — twice a month, 24 payments a year — is a different schedule and saves about $1,000. Enter your loan below to see all three side by side.
Loan Details
Interest Saved by Paying Biweekly Instead of Monthly
$88,122
70 months off the loan (5y 10m early)
Monthly vs. Bi-Monthly vs. Biweekly
Same $1,896 a month of cash out the door — only the timing changes.
Monthly
12 payments/yr
Bi-Monthly (Semi-Monthly)
24 payments/yr
Biweekly
26 payments/yr
Each schedule assumes the servicer applies every payment to principal on the day it arrives. Interest accrues on the outstanding balance at the rate for that period.
Biweekly Payment
$948
every 14 days
Interest Saved
$88,122
vs. paying monthly
Months Shaved Off
70
5y 10m early
Bi-Monthly Saves
$921
no time saved
Bi-Weekly vs. Bi-Monthly Mortgage Payments — 26 Payments a Year vs. 24
These two words get swapped constantly, and picking the wrong one costs you the entire benefit. Bi-weekly means every 14 days: 52 weeks ÷ 2 = 26 payments a year, and 26 half-payments add up to 13 full ones. Bi-monthly (properly, semi-monthly) means twice a month, usually the 1st and the 15th: 24 payments a year, and 24 halves are exactly 12 wholes. Here is the same $300,000 loan at 7% over 30 years run all three ways:
| Monthly | Bi-Monthly | Bi-Weekly | |
|---|---|---|---|
| Payments a year | 12 | 24 (twice a month) | 26 (every 14 days) |
| Adds up to | 12 full payments | 12 full payments | 13 full payments |
| What you pay | $1,995.91 / month | $997.95 on the 1st & 15th | $997.95 every 2 weeks |
| Cash out the door / yr | $23,951 | $23,951 | $25,947 |
| Total interest paid | $418,527 | $417,483 | $315,139 |
| Payoff time | 30 years | 30 years (2 weeks early) | 23 years, 9 months |
| Interest saved | — | $1,043 | $103,388 |
Same half-payments, same lender, wildly different outcome. Bi-monthly moves half your money to the lender about two weeks early each month, which stops a little interest from accruing — worth roughly $1,000 over 30 years— but the annual total is identical to paying monthly, so the term doesn't shorten. Bi-weekly costs $1,996 more a year, exactly one extra payment, and returns $103,388 and 75 fewer months of payments. The savings come from the number of payments per year, not from paying halves.
So if a servicer pitches you a “twice a month” plan, ask how many payments you will make in a calendar year. If the answer is 24, it is semi-monthly and it is not the schedule you came here for. To see either cadence laid out payment by payment, build a bi-monthly or bi-weekly amortization schedule; our biweekly payment calculator goes deeper on enrollment fees and suspense accounts.
$300,000 Mortgage at 7% — Bi-Weekly Payments Plus $100 Extra a Month
Bi-weekly and extra payments are the same lever pulled twice, and they stack. Adding $100 a month on top of a bi-weekly schedule means $46.15 extra per payment($100 × 12 ÷ 26), a bi-weekly debit of $1,044.11 instead of $997.95. Here is what each combination does to the same $300,000 loan at 7% over 30 years:
| Schedule | Payment | Per year | Total interest | Payoff | Interest saved |
|---|---|---|---|---|---|
| Monthly | $1,995.91 | $23,951 | $418,527 | 30y 0m | — |
| Bi-monthly (24/yr) | $997.95 ×2/mo | $23,951 | $417,483 | 30y 0m | $1,043 |
| Monthly + $100 extra | $2,095.91 | $25,151 | $349,189 | 25y 10m | $69,338 |
| Bi-weekly (26/yr) | $997.95 / 14 days | $25,947 | $315,139 | 23y 9m | $103,388 |
| Bi-weekly + $100/mo extra | $1,044.11 / 14 days | $27,147 | $276,802 | 21y 3m | $141,724 |
The last row is the one worth sitting with. That $100 a month — $46.15 per bi-weekly debit — buys $38,336 more in interest savings and takes another two and a half years off the payoff date, on top of what the bi-weekly switch already did. It works so hard because it arrives early: a dollar of principal retired in year two avoids 28 years of interest at 7%. Keep going and the returns keep coming, though each additional $100 buys a little less than the last:
- Bi-weekly + $100/mo ($1,044.11 every 14 days) — paid off in 21 years 3 months, $141,724 saved.
- Bi-weekly + $200/mo ($1,090.26 every 14 days) — paid off in 19 years 4 months, $171,001 saved.
- Bi-weekly + $300/mo ($1,136.42 every 14 days) — paid off in 17 years 9 months, $194,245 saved.
If round numbers are easier to actually stick to, adding a flat $50 per bi-weekly payment is $1,300 a year — a touch more than $100 a month — and finishes the loan in 21 years 1 month with $144,456 saved. Any of these amounts can be tested against your own balance in the extra payments calculator.
The same result as $166 a month in extra payments
A bi-weekly plan is an extra payment plan wearing a different schedule. Take that same $300,000 loan, keep paying monthly, and add one-twelfth of the payment — $166.33 — as extra principal each month:
- Bi-weekly ($997.95 every 14 days): paid off in 23 years 9 months, $315,139 total interest.
- Monthly + $166.33 extra ($2,162.24/month): paid off in 23 years 9 months, $316,102 total interest.
The gap is under $1,000 across three decades — bi-weekly edges ahead only because principal drops a few days sooner through the year. Both beat plain monthly by roughly $103,000. So if your servicer charges to enroll in a bi-weekly program, or parks each half-payment in a suspense account until the full amount accumulates, take the free version instead and watch principal and interest split apart period by period in the amortization schedule.
Every schedule here attacks the balance. The other lever is the rate itself, and it is only available before you close: paying discount points buys the rate down permanently, so less interest accrues in the first place. The mortgage points calculator gives you the break-even month for that trade. The two stack as well — buy the rate down, then pay bi-weekly on the cheaper loan.
How Bi-Weekly Payments Work
A biweekly schedule takes your normal monthly payment, cuts it in half, and sends that half to the lender every 14 days. Fourteen days is not half a month. The calendar has 52 weeks, so 26 half-payments land in a year — the equivalent of 13 full monthly payments instead of 12.
That thirteenth payment has no interest to cover, so all of it retires principal. Because the lender charges interest on whatever balance is outstanding, principal you retire in year three never accrues interest in years four through thirty. The effect compounds: a smaller balance means a smaller interest charge next period, which means more of the following payment goes to principal, and so on — all for one extra payment a year, spread across 26 smaller pieces instead of 12. The size of the prize scales with both balance and rate: at 7% over 30 years the switch saves $68,925 on a $200,000 loan, $103,388 on $300,000, and $137,851 on $400,000. Rate matters just as much — that same $300,000 loan saves $88,122 at 6.5% and $138,895 at 8%, because interest is exactly what you are avoiding.
You can watch the mechanism period by period in the amortization schedule. Early in a long mortgage, most of each payment is interest — which is exactly why moving a little principal forward in time has such an outsized effect on the total.
Is Bi-Weekly Better Than Monthly?
Financially, yes — as long as your loan has no prepayment penalty and you can absorb one extra payment of cash flow per year. Biweekly is better than monthly for the same reason any prepayment is: you are earning a guaranteed, tax-free return equal to your mortgage rate on every dollar of principal you retire early. At 6.5%, that is a hard return to beat with safe money.
It is the weaker choice in three situations. If your rate is very low — a 3% loan from 2021 — those dollars almost certainly work harder invested. If you are behind on retirement savings, a tax-advantaged account usually wins on an after-tax basis. And if you carry credit card or other consumer debt, that balance costs more than the mortgage interest you would be saving.
Biweekly is also not the only route to the same destination. Adding one-twelfth of your payment to each monthly bill produces the same thirteen-payments-a-year result with no enrollment fee — see the extra payments calculator. And if what you actually want is a shorter term with a lower rate rather than a self-imposed schedule, compare 15 vs 30-year mortgages — a 15-year loan locks in the discipline and typically prices below a 30-year, though the higher required payment removes your flexibility if money gets tight. For the dollar gap at specific balances, see the real cost difference between a 15- and 30-year mortgage.
Frequently Asked Questions
Is biweekly mortgage worth it?
For most borrowers, yes. On a $350,000 loan at 7% over 30 years, switching to a biweekly schedule saves about $120,600 in interest and pays the loan off roughly six years early — for one extra payment a year, split across 26 half-payments instead of 12 full ones. It is worth it whenever your loan has no prepayment penalty and you can absorb one extra payment of cash flow per year. It is the weaker choice if your rate is very low (those dollars work harder invested), if you carry higher-rate consumer debt, or if you are behind on retirement savings. And you never need to pay for a formal program to get the benefit — adding one-twelfth of your payment to each monthly bill produces the same result for free.
What is the difference between biweekly and semi-monthly mortgage payments?
It comes down to how many payments land in a year. Biweekly means every 14 days, which is 26 payments a year because the calendar has 52 weeks — and 26 half-payments add up to 13 full payments, one more than a normal year. That thirteenth payment is what pays the loan off early. Semi-monthly (often called bi-monthly) means twice a month, usually the 1st and the 15th, which is exactly 24 payments a year — and 24 halves are exactly 12 wholes. Semi-monthly gets half your money to the lender about two weeks early each month, worth a few hundred dollars over the life of the loan, but the term does not shorten. If a servicer offers a 'twice a month' plan, ask how many payments you will make in a calendar year: 24 is semi-monthly, 26 is biweekly.
What is a bi-monthly mortgage payment calculator?
Most people who search for a 'bi-monthly mortgage payment calculator' actually want the biweekly schedule. Bi-monthly is used loosely to mean twice a month — 24 payments a year, usually the 1st and the 15th. Biweekly means every 14 days, which lands 26 times a year because the calendar has 52 weeks. Twenty-four half-payments add up to exactly 12 full monthly payments, so a bi-monthly schedule barely dents your interest. Twenty-six half-payments add up to 13 full payments, and that thirteenth payment is what pays the loan off years early. The calculator above runs all three schedules so you can see which one you meant.
Does paying bi-monthly (twice a month) save any money?
Very little. Splitting your payment across the 1st and the 15th gets half your money to the lender about two weeks early each month, so a small amount of interest stops accruing sooner. On a $300,000 loan at 7% over 30 years that is worth $1,043 across three decades, and the loan still finishes within about two weeks of schedule. The same loan on a true biweekly schedule saves $103,388 and finishes 6 years, 3 months early. The savings come from the number of payments per year, not from paying halves.
Can I pay biweekly and make extra payments at the same time?
Yes, and they stack cleanly — the extra just rides along on each half-payment. On a $300,000 loan at 7%, adding $100 a month to a biweekly schedule means $46.15 more per payment: $1,044.11 every 14 days instead of $997.95. That combination pays the loan off in 21 years 3 months with $276,802 in total interest, versus 23 years 9 months and $315,139 for biweekly alone and 30 years and $418,527 for plain monthly. The extra $100 is worth $38,336 in additional interest savings on top of what the biweekly switch already delivers. Tell your servicer to apply the additional amount to principal, not to prepay the next scheduled payment — the wording matters, and the two are handled very differently.
How many payments a year is biweekly versus bi-monthly?
Biweekly is 26 payments a year: 52 weeks divided by 2. Bi-monthly (properly, semi-monthly) is 24 payments a year: 12 months times 2. Those two extra half-payments are the entire mechanism. They combine into one full extra payment that goes straight to principal, and because interest is charged on the outstanding balance, every dollar of principal retired early stops costing you interest for the rest of the term.
Should I sign up for my lender's biweekly program?
Usually not. Many servicers charge $200–$400 to enroll plus a per-payment processing fee, and some hold each half-payment in a suspense account until the full monthly amount has accumulated — which delays the principal reduction and cancels most of the benefit you enrolled for. The free equivalent is to divide your monthly payment by 12 and add that amount to each regular payment as extra principal. Before doing either, confirm with your servicer that extra principal is applied on receipt and that the loan carries no prepayment penalty.
Is biweekly better than just making one extra payment a year?
They are close to the same thing, and one extra annual payment is often the more practical version. Biweekly spreads the extra payment across 26 small increments, so principal drops slightly earlier through the year and you save a bit more interest. A single lump extra payment each December achieves nearly the same result with no schedule to manage. The gap between the two is small next to the gap between either of them and paying monthly.