One extra mortgage payment per year
"One extra payment per year" is a simple rule of thumb for paying down principal faster. It can shorten the payoff timeline and reduce total interest, especially when the extra money is applied early.
Two common ways to do it
- Make a single extra principal payment once per year (e.g., tax refund).
- Add 1/12 of a payment each month (smoother cash flow).
Why earlier usually wins
Interest is based on your outstanding balance. Reducing the balance sooner reduces future interest, so spreading the extra through the year can beat a single late-year payment.
How to model it
Start with your baseline in the Mortgage Payment Calculator. Then use the Extra Payment Mortgage Calculator as a one extra mortgage payment per year calculator and compare:
- A monthly extra equal to roughly 1/12 of your payment.
- A one-time principal-only extra once per year.
Real results can differ based on the exact day the lender applies the extra payment and how interest is calculated.
One extra mortgage payment per year inputs
- Note rate (not APR) and remaining term.
- Monthly P&I payment amount.
- Lump sum timing vs monthly extra timing.
- Servicer posting rules for principal-only extras.
Worked example: monthly extra vs one-time payment
Example: $350,000 at 6.50% for 30 years. The base payment is about $2,212. One extra payment per year is roughly $184/month or a $2,212 one-time principal payment. Timing matters, so compare a month 1 lump sum to a month 12 lump sum.
| Scenario | Payoff time | Total interest |
|---|---|---|
| Baseline (no extra) | 360 months (30y 0m) | $446,406 |
| Monthly extra $184 | 290 months (24y 2m) | $344,751 |
| One-time $2,212 in month 1 | 354 months (29y 6m) | $433,476 |
| One-time $2,212 in month 12 | 354 months (29y 6m) | $434,336 |
The earlier monthly extra usually saves more interest than a late-year lump sum, even if the totals are similar. The month 1 lump sum typically beats the month 12 lump sum because it reduces principal sooner.
How much can it save?
In the example above, the monthly-extra option saves about $101,654 in interest compared with making no extra payments. Your savings depend on rate, term, and when the extra is applied.
If your loan is already near payoff or the rate is very low, the incremental savings can be smaller.
When it might not be the best move
- You have high-interest debt or no emergency savings.
- Your loan has a prepayment penalty or fee-based payment program.
- You plan to refinance or move soon, shortening the time to benefit.
- You need liquidity more than principal reduction.
Biweekly programs vs DIY extra payments
Many biweekly programs effectively add one extra payment per year. You can often replicate the benefit by adding 1/12 of a payment monthly without paying a program fee. Always compare costs before enrolling.
Time horizon check
If you plan to sell or refinance within a few years, compare savings over that shorter window. A plan that looks great over 30 years can be less meaningful over 3 to 5 years. Model both to match your expected time in the home.
If your income is irregular
Consider a smaller monthly extra plus a year-end lump sum. This keeps the habit in place while letting you add more when cash flow is higher.
Double-check payment details
- Confirm the extra goes to principal-only, not escrow.
- Ask how quickly the payment posts to reduce interest.
- Keep receipts or statements showing principal application.
Statement check
- Verify that the extra reduces principal, not just the next due date.
- Confirm the posting date used for interest calculations.
- If your servicer posts in batches, model a later month for realism.
Checklist: make the extra count
- Ask the servicer to apply the extra to principal-only.
- Confirm there is no prepayment penalty.
- Track the payment posting date each month.
- Re-evaluate if your rate or term changes.
FAQ
Is one extra payment per year a rule or requirement?
It is just a rule of thumb. Any extra amount, at any frequency, can shorten payoff.
Does a biweekly program do the same thing?
Many biweekly programs effectively add one extra payment per year. Compare fees before enrolling.
References
- CFPB: Mortgage resources
Next steps
What to confirm with your lender
- The extra is applied to principal-only (not "paid ahead" toward the next due date).
- There is no prepayment penalty.
- Whether recasting is available if you want a lower required payment later.
Questions? Email admin@practicalfinancetools.com.
Last updated: 2026-02-08