Extra Payment Mortgage Calculator
Find out exactly how much time and interest you save by making extra monthly, annual, or one-time mortgage payments — with a full side-by-side amortization schedule.
SECTION A — LOAN DETAILS
SECTION B — EXTRA PAYMENTS
Optional: Taxes & Insurance
How to Use
- 1Enter your current loan amount, interest rate, and remaining loan term — use your latest mortgage statement for accurate figures.
- 2Enter your extra monthly payment — even $100 to $200 extra per month makes a significant difference over the life of a 30-year loan.
- 3Optionally add an extra annual lump sum (such as a tax refund or year-end bonus) and a one-time extra payment applied at the start.
- 4Click Calculate to see your new payoff date, total interest saved, and the full side-by-side amortization schedule.
Example Calculation
Original Loan
With All Extra Payments
"By adding $200/month, $1,200/year, and a $5,000 one-time payment, you save $135,425.46 in interest and pay off your mortgage 8 years early."
Results assume extra payments are applied directly to principal. Contact your lender to confirm your loan allows early principal payments without penalty.
Frequently Asked Questions
Q1: How are extra payments applied to my mortgage?
A1: This calculator assumes all extra payments are applied directly to your loan principal, which reduces your outstanding balance and therefore the interest that accrues in future months. In practice, you must specify to your lender that extra payments should be applied to principal — not to future payments. Always verify your loan has no prepayment penalty before making extra payments.
Q2: How much interest does an extra $200/month save on a $300,000 mortgage?
A2: On a $300,000 loan at 7.0% for 30 years, adding $200 extra per month saves $116,640.00 in interest and pays off the loan 7.1 years (85 months) early. The earlier in the loan you start making extra payments, the greater the savings — because interest is calculated on the remaining balance, so reducing the balance early has a compounding effect throughout the loan.
Q3: Is it better to make extra monthly payments or one larger annual payment?
A3: Monthly extra payments are slightly more efficient because they reduce your principal balance sooner, meaning less interest accrues each month. However the difference is small. A $200/month extra saves $116,640.00, while adding a $1,200 annual lump sum on top saves an additional $33,135.63 — bringing total savings to $149,775.63 and cutting 9.2 years off the loan. Use whatever extra payment frequency best fits your cash flow.
Q4: Does a one-time extra payment early in the loan make a big difference?
A4: Yes — a one-time $5,000 payment at month 1 on a $300,000 loan saves approximately $18,785.46 in additional interest when combined with $200 extra per month, cutting the payoff by an additional 11 months compared to the extra monthly payment alone. This is because every dollar applied to principal early in the loan eliminates the highest-interest portion of the remaining amortization schedule.
Q5: What is the best strategy for paying off a mortgage faster?
A5: The most effective strategy combines all three types of extra payments: a consistent extra monthly amount (automated so you never miss it), an annual lump sum from a bonus or tax refund, and any windfall amounts applied as one-time payments. On a $300,000 loan at 7.0%, combining $200 extra per month, $1,200 annual, and a $5,000 one-time payment cuts 8 full years off the loan and saves over $135,000 in interest — without changing your lifestyle significantly.
This calculator provides estimates for informational purposes only. Actual savings and payoff dates depend on your specific loan terms and lender guidelines. Consult a licensed mortgage professional before making financial decisions.