See how extra payments, bi-weekly, and lump sums cut years off your mortgage.
Test any combination of extra-payment strategies — monthly, bi-weekly, or yearly lump sum — and see exactly how many years come off and how much interest you save.
Direct answers to the most common questions, in plain language. Skim if you're in a hurry; dig deeper below.
$100/mo extra typically saves 4–6 years and 20–30% of interest.
On a 30-year, $300k mortgage at 7%, an extra $100/month cuts the loan by about 5 years and saves roughly $80,000 in interest. The savings scale roughly linearly with the extra amount.
Yes — and it's 13 months of payments per year, not 12.
Paying half your mortgage every 2 weeks results in 26 half-payments per year — equivalent to 13 full monthly payments. That one extra payment per year shaves 4–5 years off a typical 30-year mortgage.
Refinance for rate drops; extra payments for accelerated payoff.
Refinancing makes sense if rates drop 0.75%+ and you'll stay in the home long enough to recoup closing costs. Extra payments work at any rate — they're a guaranteed return equal to your mortgage rate.
Almost never on US conventional, FHA, or VA loans.
Federal regulations effectively prohibit prepayment penalties on most owner-occupied conventional, FHA, VA, and USDA loans. Some non-conforming or older loans may have penalties — check your note.
The mechanics in short answers — no jargon, no upsell.
Anything paid above your scheduled P&I goes 100% to principal. The next month's interest calculation uses the new, lower balance.
In year 1 of a 30-year loan, 75% of your payment is interest. An extra dollar in year 1 saves far more than the same dollar in year 25.
26 half-payments per year ≠ 24. The "extra two halves" become one full extra payment that goes straight to principal.
A $10,000 tax refund applied to principal in year 3 saves dramatically more than spreading it out — earlier is always better.
Designed so anyone can model their situation in under a minute, with or without a finance background.
Even modest extras shorten the loan by years — see the exact months.
Tens of thousands over the life of the loan, guaranteed return at your rate.
Monthly extra, bi-weekly, one extra payment per year, lump sum — compare all four.
Watch your debt-free date slide forward in real time.
Extra payments are a guaranteed return — no market exposure, no fees, no taxes.
Pause or accelerate extras any month — flexibility that refinance doesn't offer.
Everything you might ask before, during, or after using this tool.
A guaranteed 7% return (your mortgage rate) is hard to beat after taxes and risk. If your mortgage rate is below ~5%, investing in equities often wins long-term. If above ~6.5%, extra payments usually win. Around 5.5–6.5% is the messy middle — many people do both.
No — most lenders apply extras to principal but keep your monthly payment the same and shorten the loan. To "recast" (reduce the monthly), you usually pay a small fee ($250–500) and request it explicitly. Most borrowers don't recast because shortening the loan saves more interest.
Yes, slightly — bi-weekly results in one extra payment per year, plus the timing means interest is calculated on a slightly lower balance throughout the year. Total savings vs. straight monthly is usually 4–5 years and 15–20% interest reduction.
Almost always yes — assuming your high-interest debt is paid off and emergency fund is funded. A $10,000 lump sum applied to a 7% mortgage in year 3 saves roughly $25,000 in interest over the remaining loan.
Yes — be explicit. Write "apply to principal" on a check, or use the principal-only option in online banking. Otherwise some servicers credit it as "next month's payment," which costs you interest savings.
Mortgage interest deduction matters less than it used to. After the 2017 SALT cap, most homeowners take the standard deduction and lose the mortgage-interest benefit anyway. Even with the deduction, the math typically still favors paying extra.
On a 30-year, $300k loan at 7%, paying about $400/month extra cuts the loan by roughly 10 years. The exact amount scales with loan size and rate — use this calculator with your specific inputs to find your target.
Emergency fund first, always. A 3–6 month fund is non-negotiable. Once that's funded, extra payments become a powerful tool. Skipping the fund to pay extra is fragile — one job loss undoes years of acceleration.
Other Lazysmirk tools that pair well with this one.
See how extra EMI payments, yearly prepayments, and lump-sum part payments reduce your home loan tenure and save thousands in interest.
Calculate your true monthly mortgage payment with taxes, insurance, and PMI included. See how much interest you'll actually pay over 30 years.
Find out if refinancing your mortgage actually saves money. Break-even month, lifetime interest savings, and the term-reset trap — all in one calculator.
See the full month-by-month amortization schedule for any loan — EMI, principal vs interest split, and total interest paid. Works for home, car, personal, and student loans.
Find out how much house you can afford. Enter income, debts, down payment, and rate to get your max home price, recommended budget, monthly PITI, and the binding constraint.
Interest is calculated on remaining principal every month. Pay an extra $200 in year 2 of a 30-year loan and you erase $200 of principal that would have accrued interest for 28 more years.
That compounding-against-you-not-happening is where the savings come from. It's identical math to compound investing — just running in your favor.
Monthly extra: simplest, most flexible. Pick an amount and add it to every payment.
Bi-weekly: 13 monthly payments per year instead of 12. Hands-off acceleration.
Annual extra payment: send one extra full payment each year, usually January.
Lump sum from bonus/refund: rare but powerful — earliest dollars matter most.
Default behavior: extras shorten the loan, monthly payment stays the same.
Recast: for a small fee, the lender re-amortizes the loan with the new lower balance — your monthly payment drops, but the savings are smaller than just letting the loan shorten.
Pick shorten unless you actively need lower monthly cash flow.
Math: compare your mortgage rate to your after-tax expected investment return.
Below 5%: investing usually wins long-term.
Above 6.5%: extra payments usually win.
5.5–6.5%: muddy. Many people split 50/50.
Don't ignore the behavioral angle — guaranteed savings feels different from variable returns. That matters.
Two short notes worth reading before you trust any number on this page.
Your loan amount, rate, and prepayment inputs never leave your device. No accounts, no cookies on your numbers, no analytics on the values you type. Disconnect from the internet and it still works.
We are not a bank, NBFC, advisor, broker, or distributor of any financial product. The numbers shown here are estimates for educational purposes only, based on the inputs you provide.
Results are not financial, legal, or tax advice. Please consult a qualified professional before any decision about your loan, investments, or personal finances. Actual loan terms and charges depend on your bank and individual circumstances.
