Biweekly Payment Calculator
Find out how much time and interest an accelerated biweekly plan removes from your mortgage, and why paying the same amount more often does almost nothing.
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What biweekly payments actually do
Biweekly mortgages are marketed as a way to pay off a loan years early, and they do work — but almost never for the reason people think. The saving does not come from paying more often. It comes from paying more.
This matters because the two are easy to confuse. If you divide a monthly instalment by two and pay that every two weeks, you make 26 half-payments a year, which is 13 full instalments instead of 12. You have paid one extra monthly payment every year without noticing, and that extra principal is what shortens the loan. Paying the same annual total fortnightly instead of monthly saves almost nothing, because the nominal rate divided by 26 rather than 12 compensates for the extra frequency.
On a 300,000 dollar loan at 6.5 percent over 30 years, the monthly payment is 1,896.20 dollars. Halving it gives 948.10 dollars every two weeks, which is 24,650.60 dollars a year instead of 22,754.40 dollars. That extra 1,896 dollars annually removes interest from every remaining month, and the loan finishes in about 24 years and 2 months instead of 30. Total interest falls from 382,633 dollars to 294,512 dollars — a saving of 88,122 dollars.
The catch is administrative rather than mathematical. Many lenders charge a setup fee for a formal biweekly programme, and some hold your half-payments until a full one has accumulated, which delays the interest saving. You can reproduce the entire benefit for free by paying one extra monthly instalment a year against principal and marking it clearly as principal, which is the option worth comparing against whatever the lender is selling.
How the comparison is calculated
Two schedules are run on the same loan: the standard monthly plan, and a plan paying half that instalment every two weeks.
| Symbol | Meaning |
|---|---|
Monthly payment |
The standard instalment from the amortisation formula |
Biweekly payment |
Exactly half of it, paid every two weeks |
26 |
Fortnights in a year, giving thirteen full instalments instead of twelve |
i |
Periodic rate: the annual rate divided by 26 for the biweekly schedule |
Period counts differ between the two plans (360 against 628) and comparing them directly is meaningless, so the difference is reported in calendar time — months saved — rather than in periods.
Worked example: 300,000 dollars at 6.5 percent over 30 years
The same loan run on a monthly plan and on an accelerated biweekly plan.
| Figure | Monthly plan | Biweekly plan |
|---|---|---|
| Payment | $1,896.20 a month | $948.10 every two weeks |
| Payments each year | 12 | 26 |
| Extra paid each year | — | $1,896.20 |
| Time to pay off | 30 years | 24 years 2 months |
| Time saved | — | 70 months |
| Total interest | $382,633.47 | $294,511.68 |
| Total paid | $682,633.47 | $594,511.68 |
| Interest saved | — | $88,121.78 |
You pay an extra 1,896 dollars a year, spread out as roughly 79 dollars a fortnight, and the loan finishes almost six years early. The 11,398 dollars of extra payments across the shortened term is not a cost: it reduced your own debt. The genuine saving is the 88,122 dollars of interest that was never charged.
Estimates only. Your lender's figures may differ because of fees, escrow and rounding.
Getting the benefit without paying a fee
Replicate it yourself and keep the money
Paying one extra monthly instalment a year against principal produces almost exactly the same result as a formal biweekly programme, and costs nothing. Mark the payment clearly as principal so the lender does not hold it as a credit against next month's instalment.
Check what the lender's programme actually charges
Setup fees of several hundred dollars are common, and some programmes charge a per-payment transaction fee. Run the numbers: if the saving is 88,122 dollars then a 400 dollar setup fee is trivial, but a 5 dollar fee on 628 payments is over 3,000 dollars.
Make sure the half-payments are applied immediately
Some lenders accumulate your fortnightly payments and only apply them when a full monthly instalment has built up. That removes most of the benefit, because the interest saving depends on principal being reduced as early as possible. Ask explicitly how and when each payment is applied.
Consider whether the cash is better used elsewhere
The plan commits an extra 1,896 dollars a year for 24 years. If you are carrying credit card debt above 20 percent, every dollar sent there earns more than the 6.5 percent this saves. Clear expensive debt first, then accelerate the mortgage.
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Frequently asked questions
Do biweekly payments really pay off a mortgage faster?
Yes, because you make 26 half-payments a year, which equals 13 full instalments instead of 12. On a 300,000 dollar loan at 6.5 percent that removes about 70 months from the term and saves roughly 88,000 dollars in interest. The saving comes from the extra payment, not the frequency.
Does paying monthly twice a month save the same amount?
No. Paying half the instalment on the 1st and half on the 15th is still only 12 instalments a year. The benefit requires 26 payments, which means paying every two weeks rather than twice a month, and that is what produces the thirteenth instalment.
Should I use the lender's biweekly programme or do it myself?
Doing it yourself is usually better. Pay one extra monthly instalment a year against principal and label it as principal, which produces nearly the same result with no setup fee and no per-payment charge. The formal programme is only worth it if your lender charges nothing and applies each half-payment immediately.
Is it better to pay biweekly or to make one lump sum a year?
They are closer than they look. The fortnightly plan reduces principal earlier within each year, which saves slightly more interest, but an annual lump sum is easier to manage and does not depend on a lender applying payments promptly. Both beat doing nothing by a wide margin.
Do biweekly payments hurt my credit score?
No. Paying more often does not affect your score, and reducing the balance faster improves your loan-to-value ratio over time, which helps if you later apply for a refinance or a home equity line. The only risk is missing a payment through the added complexity.