Want to test your own biweekly vs. extra-payment numbers first?
Try the Free Calculator →I built the Extra Mortgage Payment Calculator for CalcFactor — and today I finally ran my own numbers through it. I tested two scenarios: switching to biweekly payments with $200 extra, and paying $400 extra monthly. The results genuinely surprised me.
Scenario 1 — Biweekly + $200 extra: saved $37,600 and nearly 5 years.
Scenario 2 — $400 extra monthly: saved $41,100 and over 5 years.
Same mortgage. Two different strategies. And the winner wasn't the one I expected.
Here's exactly what I plugged in for both scenarios:
Biweekly payment of $931 every two weeks, plus $200 extra toward principal. That's 26 half-payments per year — the equivalent of 13 full monthly payments instead of 12. The extra annual payment goes straight to principal with no interest attached.
Standard monthly payments with $400 extra applied directly to principal each month. No schedule change — just more money going to principal every single month consistently.
Honestly? So did I. Biweekly payments feel more aggressive. You're paying more frequently, you're making 26 payments a year instead of 12 — it sounds like it should come out ahead.
"I built the calculator. I ran my own numbers. And the result still surprised me — extra monthly payments beat biweekly by $3,500 and almost 5 months."
Here's why. With biweekly payments, you're effectively making one extra full payment per year. That's the secret sauce — 26 half-payments = 13 full monthly payments instead of 12. Good. But with $400 extra monthly, you're putting an additional $4,800 per year directly to principal — every single month, consistently, from day one.
$4,800 per year beats one extra $1,862 payment per year. The math is straightforward once you see it — but it's not what most people intuitively expect.
Even though extra monthly won in my scenario, biweekly payments are still powerful — and for many people they're actually the easier strategy to stick with.
There are 52 weeks in a year. Pay every two weeks and you make 26 half-payments — equal to 13 full monthly payments instead of 12. That one extra payment goes entirely to principal with no interest attached. And because your balance drops faster, every future payment has less interest — the savings compound over 20 years into $37,600.
The reason biweekly works so well psychologically is that it aligns with biweekly paychecks. You pay $931 when your check hits and you barely notice it. Whereas committing to $400 extra every month requires more discipline to maintain consistently.
Here's where it gets important. Just because you want to pay biweekly doesn't mean your lender will apply it that way automatically.
Most major servicers do allow it, but you have to confirm. Some even have a biweekly program you can enroll in online. Others require you to write "apply to principal" in the memo line or submit through a specific portal option.
This is the question I get asked a lot. The honest answer is: they're very similar in impact, but they feel different psychologically.
The calculator I built lets you combine all three — extra monthly, lump sum, and biweekly — so you can see exactly what each approach saves and decide what fits your cash flow.
Run your own biweekly mortgage numbers — see exactly what you'd save
Try the Free Calculator →On paper — $400 extra monthly wins. It saves $3,500 more in interest and gets the mortgage paid off 5 months sooner than biweekly. The math is clear.
But here's the thing about personal finance: the best strategy is the one you'll actually stick to.
"The $400 extra monthly saves more — but biweekly payments feel invisible. You pay $931 every two weeks and barely notice it aligning with your paycheck."
If you get paid biweekly, the biweekly mortgage strategy is psychologically effortless. The payment comes out with your paycheck rhythm. You never have to think about it or remember to send extra. That consistency has real value.
If you have more flexibility and cash flow discipline, the $400 extra monthly is the stronger choice mathematically — $41,100 saved and paid off by June 2041.
I'm going with the $400 extra monthly. The $3,500 difference matters to me and I have the discipline to keep it consistent. But I completely understand why biweekly is the better fit for most people — it removes the decision entirely.
Either way, both strategies save tens of thousands of dollars and shave years off the loan. The worst option is doing nothing and just paying the minimum for 20 more years.
"$41,100 saved on a mortgage I already have. No refinancing. No new loan. Just paying smarter."
My next step is calling my loan servicer to confirm extra payments go directly to principal — not held as a future payment. That one call is the step most people skip and it's the most important one.
It varies with your balance, rate, and years remaining, but the mechanism is consistent — you're making one extra full payment per year. On a $300K balance at 4.375% with 20 years left, that worked out to $37,600 in my case. On a higher-rate loan, the savings would be larger; on a lower balance, smaller.
Some third-party "biweekly payment services" charge setup fees or per-transaction fees to automate this for you — skip those. You can achieve the same result for free by manually sending an extra principal payment once a year, or by asking your servicer directly if they offer free biweekly enrollment.
Then the biweekly structure doesn't save you anything — your money just sits until your next scheduled payment is due. In that case, skip biweekly and instead send one lump extra payment per year, explicitly marked for principal reduction, which achieves the same result without depending on your servicer's payment processing.
No — your required minimum payment doesn't change with either strategy. Lenders evaluating your debt-to-income ratio look at your required payment, not what you're voluntarily paying extra.
If you're using an official biweekly program through your servicer, check their specific terms — some lock you in. If you're simply sending an extra annual lump sum yourself, you have complete flexibility to skip a year if needed, which is one reason some people prefer that approach over a formal biweekly enrollment.
Not at all — the earlier in the loan you start, the more total interest you save, but even starting midway through still saves meaningful money and time, since every dollar of extra principal reduces interest for all remaining months of the loan.
They solve different problems. Biweekly/extra payments keep your flexibility and current rate while paying off faster informally. Refinancing to a 15-year term locks in a formal shorter schedule and often a lower rate, but comes with closing costs and requires re-qualifying. If your current rate is already low, extra payments are usually the better move.
See how much YOU could save with biweekly or extra payments on your mortgage
Calculate My Savings →