Biweekly Mortgage Calculator
Compare monthly payments with true biweekly half-payments (26 a year = 13 monthly payments) and see the interest saved and years cut from your mortgage.
Biweekly Mortgage Calculator: with the default inputs, interest saved with biweekly payments is $93,997.
Original loan, or your current balance if you're switching mid-loan (then enter the years remaining).
- Time saved
- 5 years, 10 months
- Biweekly payment
- $1,011.31Half the monthly payment, every two weeks.
- Monthly payment
- $2,022.62
- Payoff date (biweekly)
- September 22, 2050
- Payoff date (monthly)
- August 10, 2056
- Total interest (biweekly)
- $314,146
- Total interest (monthly)
- $408,142
- Extra paid per year with biweekly
- $2,02326 halves − 12 months = one extra monthly payment a year.
Assumptions
- Biweekly payments are exactly half the monthly payment, made every 14 days (26 per year), with interest charged per period at the annual rate ÷ 26.
- Monthly payments are level with interest at the annual rate ÷ 12; both schedules are fixed-rate with no fees or prepayment penalties.
| Year | Monthly | Biweekly | Biweekly is ahead by |
|---|---|---|---|
| 1 | $316,423 | $314,331 | $2,092 |
| 2 | $312,607 | $308,281 | $4,326 |
| 3 | $308,535 | $301,826 | $6,709 |
| 4 | $304,191 | $294,938 | $9,253 |
| 5 | $299,555 | $287,588 | $11,967 |
| 6 | $294,609 | $279,745 | $14,865 |
| 7 | $289,332 | $271,375 | $17,957 |
| 8 | $283,701 | $262,445 | $21,257 |
| 9 | $277,694 | $252,915 | $24,778 |
| 10 | $271,284 | $242,747 | $28,537 |
How this is worked out
The formula
Monthly payment M = P × r(1 + r)^n ÷ ((1 + r)^n − 1), r = rate ÷ 12 Biweekly payment = M ÷ 2, paid 26 times a year (= 13 monthly payments) Each biweekly period: interest = balance × rate ÷ 26; principal = M/2 − interest Interest saved = total interest (monthly) − total interest (biweekly)
Open How it’s calculated above to see this worked through with your own numbers.
What you enter
- Loan amount
- Original loan, or your current balance if you're switching mid-loan (then enter the years remaining).in dollars · 0 or more · defaults to 320000
- Interest rate
- A number.a percentage · from 0 to 30 · defaults to 6.5
- Term
- A number.from 1 to 40 · whole numbers only · defaults to 30
- First payment date(under More options)
- A calendar date.defaults to today
What you get back
- Interest saved with biweekly paymentsmain answer
- Time saved
- Biweekly payment
- Half the monthly payment, every two weeks.
- Monthly payment
- Payoff date (biweekly)
- Payoff date (monthly)
- Total interest (biweekly)
- Total interest (monthly)
- Extra paid per year with biweekly
- 26 halves − 12 months = one extra monthly payment a year.
What this assumes
- Biweekly payments are exactly half the monthly payment, made every 14 days (26 per year), with interest charged per period at the annual rate ÷ 26.
- Monthly payments are level with interest at the annual rate ÷ 12; both schedules are fixed-rate with no fees or prepayment penalties.
About this calculator
A biweekly mortgage plan sounds like an accounting trick, and in a sense it is: you pay half your monthly payment every two weeks, and because there are 52 weeks in a year, you make 26 half-payments — 13 full payments instead of 12. That one extra payment a year goes entirely to principal. On a 30-year loan it typically cuts five to six years off the term and saves a fifth or more of the total interest. This calculator runs the two schedules side by side so you can see exactly what it's worth on your loan.
How to use it
Enter the loan amount, rate and term. If you're mid-way through a mortgage, use your current balance and the years remaining. Set the first payment date under More options to get real payoff dates. The chart shows both balances by year; the table shows how far ahead the biweekly plan is at each point.
Reading the results
- Interest saved is the headline, and it's real money — but it arrives over decades, not this year.
- Time saved is the years you don't spend paying.
- Extra paid per year is simply one monthly payment; that's the whole mechanism. You could get the same result by adding one-twelfth of your payment to each monthly bill, or by making one extra full payment every December.
Do it yourself, don't pay for it
Many servicers accept biweekly drafts at no charge. Some don't, and third-party "biweekly programs" fill the gap by collecting your half-payments, holding them, sending a normal monthly payment, and forwarding the extra once a year — for an enrollment fee of a few hundred dollars plus per-transaction charges. Skip them. Adding 1/12 of your payment to the principal each month achieves the same thing, with no fee and no risk that your money is sitting in someone else's account.
Two conventions
Some lenders that offer true biweekly loans compute interest per 14-day period at rate ÷ 26, which is what this calculator does. Others simply hold your halves and post a monthly payment plus the extra once a year. The savings differ by a few hundred dollars over the life of the loan; the years and the bulk of the interest saved are the same either way.
When biweekly isn't the best move
The extra payment earns a guaranteed return equal to your mortgage rate. If you carry card debt at 20%, haven't captured your 401(k) match, or have no emergency fund, those come first. And if your rate is well below what safe investments pay, prepaying is optional rather than obvious.
Frequently asked questions
▸How much does paying biweekly save on a mortgage?
On a 30-year loan at 6–7%, typically five to six years and 20–25% of the total interest — on $320,000 at 6.5% that's about $94,000. The saving comes from making the equivalent of one extra monthly payment a year.
▸Is biweekly the same as making one extra payment a year?
Essentially, yes. 26 half-payments equal 13 monthly payments. Adding one-twelfth of your payment to each month's bill, or one full extra payment each year, produces nearly identical results.
▸Will my lender let me pay biweekly?
Many do at no cost; ask whether they apply each half when received or hold it until month-end. If they charge a fee or don't offer it, just add 1/12 of your payment to principal every month instead.
▸Should I use a third-party biweekly payment service?
No. They charge setup and per-payment fees to do something you can do free, and they hold your money between payments. The math they advertise is exactly what this calculator shows.
▸Does biweekly lower my interest rate?
No — the rate is fixed. You pay less total interest because the balance falls faster and interest is charged on a smaller balance for fewer years.
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