Is biweekly really 14-day interest?

Usually not. Nearly all US servicers accrue interest monthly and simply apply your half-payments as they pair up, with the leftover becoming one extra payment a year. A few lenders, mostly credit unions, do accrue every fourteen days — that pays off slightly faster than this calculator shows. Ask your servicer which they do.

Should I pay a service to set this up?

Usually not. Third-party biweekly services charge setup and per-payment fees, and many forward your money to the servicer monthly anyway — holding the extra back as a 13th annual payment. That is the same math you can get for free by paying a little extra yourself.

Is biweekly better than just paying extra monthly?

Slightly worse, in fact. Both put one extra payment a year against the loan, but paying one twelfth extra each month applies the money sooner, so it saves a little more interest. The comparison table above shows both for your numbers.

What if my servicer does not offer biweekly?

You can reproduce the effect yourself by adding one twelfth of your scheduled payment as extra principal each month, or by making one additional full payment a year. Confirm on your statement that it is applied to principal rather than held as a future payment.

Biweekly Mortgage Calculator

Paying half your mortgage every two weeks means 26 payments a year — one extra full payment. See what that actually saves, and how it compares to paying the extra yourself.

Biweekly payment

$1,011.31 every 2 wks

Half of the $2,022.62 monthly payment, paid every two weeks

Time saved

5 yr 9 mo

Interest saved

$91,480.86

Payoff date

Dec 1, 2050

Instead of

Sep 1, 2056

on a plain monthly schedule

Savings depend on your servicer applying the extra payment to principal.

Confirm the extra actually reaches principal
These savings only happen if your servicer applies the extra payment to principal rather than holding it as your next scheduled payment. Check your statement after the first extra lands.
Paying the extra yourself does slightly better
Adding 1/12 of your payment as extra principal every month puts the same money to work sooner than a servicer's biweekly programme, which holds it until a full payment accumulates. It costs nothing and needs no third party — one reason to be sceptical of paid biweekly services.

Biweekly versus paying the extra yourself

A biweekly schedule works because you make one extra payment a year. You can do exactly the same thing without a programme — and slightly better, because the money reaches principal every month instead of waiting for a full payment to accumulate.

Payoff and interest for a monthly schedule, a servicer biweekly programme, and paying one twelfth extra each month
Approach	You pay	Saves
Standard monthly	$2,022.62every month	baseline
Biweekly through your servicer	$1,011.31every two weeks	$91,480.865 yr 9 mo early
Monthly, plus 1/12 extra yourselfbest	$2,191.17every month	$93,072.075 yr 10 mo early

Assumptions used

Assumption set 2026-04-30

Biweekly model: Servicer-applied (monthly interest accrual)calculated; Interest accrues monthly, as almost all US servicers compute it. The 26 biweekly payments cover 12 monthly payments plus one extra full payment a year, which goes to principal.
This is not true 14-day amortization. A handful of lenders — mostly credit unions — accrue interest every fourteen days, which pays off slightly faster than shown here.
Timing of the extra payment: Two half-payments a year, in months 6 and 12default; Biweekly dates drift against calendar months, so roughly twice a year a month contains three payment dates. Exact timing varies by servicer and start date; the payoff differs by a month at most.

Biweekly Payment Comparison

Generated … · Assumption set 2026-04-30

How this calculator works

A biweekly schedule means paying half your scheduled monthly amount every two weeks. Because there are 52 weeks in a year, that is 26 half-payments — the equivalent of 13 monthly payments rather than 12. The extra payment goes to principal, which shortens the loan and cuts total interest. This calculator models the way nearly all US servicers apply biweekly payments: interest still accrues monthly, and the extra reaches principal as one additional full payment each year. A small number of lenders instead accrue interest every fourteen days, which pays off marginally faster than shown here.

Reviewed for calculation accuracy and clarity by the Mortgage Well Calculation Review Team · September 1, 2026

When to use this

Your servicer offers a biweekly programme and you want to see what it is worth before enrolling.
A third-party biweekly service has quoted you a fee and you want to check the math yourself.
You want to know whether paying a little extra each month gets you the same result.

Methodology

We compute the scheduled monthly payment with the standard fully-amortizing formula, then halve it for the biweekly amount. Across a year, 26 half-payments cover the 12 scheduled monthly payments and leave two halves over. Biweekly dates drift against calendar months, so those two halves land roughly six months apart; we apply them as extra principal in months 6 and 12 of each year. Interest accrues monthly throughout, matching how servicers actually compute it.

biweekly = round(monthly / 2)
26 x biweekly  =  13 x monthly
extra principal per year = 2 x biweekly = 1 monthly payment

Interest each month = balance x (annual rate / 12)

Assumptions

Interest accrues monthly, as nearly all US servicers compute it — not every fourteen days.
The two extra half-payments are applied in months 6 and 12 of each year; exact timing varies by servicer and start date, which moves the payoff by at most a month.
The extra is applied to principal. If your servicer holds it as a future scheduled payment instead, none of these savings happen.
Fixed rate, fully amortizing, no fees. Third-party biweekly services often charge setup and per-payment fees that are not modelled here.

Example

On a $320,000 loan at 6.5% over 30 years, the scheduled monthly payment is about $2,022, so the biweekly payment is about $1,011. Through a servicer's biweekly programme the loan pays off about 5 years 9 months early, saving roughly $91,481 in interest. Paying one twelfth of the monthly payment — about $169 — as extra principal each month instead saves about $93,072 and pays off a month sooner, because the money reaches principal without waiting for a full payment to accumulate.

Frequently asked

Is biweekly really 14-day interest?: Usually not. Nearly all US servicers accrue interest monthly and simply apply your half-payments as they pair up, with the leftover becoming one extra payment a year. A few lenders, mostly credit unions, do accrue every fourteen days — that pays off slightly faster than this calculator shows. Ask your servicer which they do.
Should I pay a service to set this up?: Usually not. Third-party biweekly services charge setup and per-payment fees, and many forward your money to the servicer monthly anyway — holding the extra back as a 13th annual payment. That is the same math you can get for free by paying a little extra yourself.
Is biweekly better than just paying extra monthly?: Slightly worse, in fact. Both put one extra payment a year against the loan, but paying one twelfth extra each month applies the money sooner, so it saves a little more interest. The comparison table above shows both for your numbers.
What if my servicer does not offer biweekly?: You can reproduce the effect yourself by adding one twelfth of your scheduled payment as extra principal each month, or by making one additional full payment a year. Confirm on your statement that it is applied to principal rather than held as a future payment.

Sources and references

Helpful consumer references used to explain assumptions on this page. These are educational pointers, not regulatory endorsement.

CFPB — Loan Estimate explainer — consumer guidance on what a real lender Loan Estimate contains; this calculator is not one
Internal — fully-amortizing fixed-rate formula — standard P&I formula, taxes/insurance divided to monthly amounts

Estimates only. This calculator is not a loan offer, loan approval, official Loan Estimate, Closing Disclosure, tax advice, legal advice, or financial advice. Actual payments, rates, taxes, insurance, mortgage insurance, closing costs, and loan terms may vary. Contact a qualified lender, tax professional, or financial advisor for guidance.