Lump Sum vs. Monthly Extra Mortgage Payments: Which Saves More?
We ran $12,000 of extra payments five different ways on a $300,000 loan. Here is which saves the most, and when each method makes sense.
- Same money, earlier = more savings. On a $300,000 loan at 7%, a $12,000 lump sum in month one saves about $73,500 in interest. Paying $1,000 a month for the first year saves about $71,100. The same $12,000 at the end of year one saves about $68,800.
- Waiting costs you. The same $12,000 paid in year five saves only about $50,800.
- Small but steady also works: $100 a month for ten years ($12,000 total) saves about $51,800.
- Pick the method you’ll actually stick with, then send the money to principal.
You’ve got some extra cash, maybe a bonus, a tax refund or an inheritance, and you want to put it toward the mortgage. Should you send it all at once, or spread it out over the year? The math has a clear winner, but it’s closer than most people think, and the “best” choice depends on more than math.
The head-to-head: $12,000 five different ways
Here’s a $300,000, 30-year fixed loan at 7%, with $12,000 of extra payments sent five different ways:
| How you pay the extra $12,000 | Paid off early by | Interest saved |
|---|---|---|
| Lump sum in month 1 | 3 yrs 6 mos | $73,516 |
| $1,000 a month for the first 12 months | 3 yrs 5 mos | $71,139 |
| Lump sum at the end of year 1 | 3 yrs 4 mos | $68,791 |
| $100 a month for 10 years | 2 yrs 7 mos | $51,793 |
| Lump sum in year 5 | 2 yrs 7 mos | $50,792 |
The rule is simple: the sooner a dollar hits principal, the more interest it avoids. A lump sum today beats the same money spread over the next year, which beats the same money paid later. Try your own numbers in the extra payment calculator.
When a lump sum makes the most sense
- You got a one-time windfall and your emergency fund is already full.
- You want a lower monthly payment. A big lump sum plus a mortgage recast can lower your payment without refinancing. Many servicers require a minimum lump sum for a recast, so ask first.
- You’re close to removing PMI. A lump sum that gets you to 20% equity can let you ask your servicer to drop private mortgage insurance on a conventional loan.
When monthly extra payments make more sense
- You don’t have a lump sum. $100 or $200 a month adds up to big savings over time. See what $100 extra a month does, or one extra payment a year.
- You want to keep a cushion. Once money goes into your house, you can’t easily get it back without a loan like a HELOC or home equity loan.
- Your income changes. Monthly extras are easy to pause in a tight month. A lump sum, once sent, is gone.
A middle path: send it as you get it
If extra money comes in bits, like side income or small refunds, don’t wait to collect a big pile. Send each amount to principal when it arrives. You get nearly all the savings of a lump sum without having to plan around one.
Whichever way you choose, label every extra payment “principal only.” Otherwise your servicer may count it as an early regular payment. Also check for a prepayment penalty. They’re rare, but if your loan has one, a big lump sum in the first three years could trigger it.
Before you send a big check
- Pay off any high-interest debt first.
- Keep at least three to six months of expenses in savings.
- Make sure you’re getting your full employer retirement match.
- Compare with investing. Our side-by-side, pay off your mortgage or invest?, runs the numbers.
FAQ
Is it better to make a lump sum payment or extra monthly payments?
For the same total, a lump sum paid now saves slightly more than spreading it out, because the balance drops sooner. The gap is usually small, so choose the method you can stick with.
Will a lump sum payment lower my monthly payment?
Not automatically. It shortens the loan. To lower the payment, ask your servicer about a recast after the lump sum.
Is there a limit on how much extra I can pay?
Most loans let you pay as much extra as you want. A few older or special loans have limits or penalties, so check your note.
Should I pay a lump sum on my mortgage or keep it in savings?
Keep your emergency fund first. After that, extra principal earns a guaranteed “return” equal to your mortgage rate, which is hard to beat with no risk.
Sources: Consumer Financial Protection Bureau (payment crediting, PMI removal and prepayment rules). All payment, interest and time-saved figures computed by Keys & Coffee using standard amortization math on a $300,000, 30-year loan at 7%. This article is general education, not financial advice. Keys & Coffee is not a lender.
Written by
Shivam Kaushik· IMSHIVA
Founder & Director, QuibbleTech Solutions Pvt Ltd · Editor, Keys & Coffee
Shivam Kaushik is the founder of QuibbleTech Solutions Pvt Ltd and the editor of Keys & Coffee. He is not a licensed loan officer or financial adviser. Every guide here is written in plain English and checked against official sources such as the CFPB, HUD, Fannie Mae, Freddie Mac and the Federal Reserve. For advice on your own loan, talk to a licensed lender.
Keys & Coffee is an independent education site. We are not a lender or mortgage broker, we do not take loan applications or payments, and nothing here is financial advice. This site is not affiliated with Axia Home Loans, Axia Financial, LLC, or Planet Home Lending. Rates and rules change often — always confirm details with a licensed loan officer and check any lender on the NMLS Consumer Access site.
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