Mortgage Payoff Accelerator
See how much interest and how many years you can cut with extra payments, find out if a refinance really pays off, and compare paying down the loan against investing the money instead.
Your loan and plan
Your loan, with and without extra payments
Where your money goes
Total paid over the life of the loan.Milestones
When you hit each one.What the numbers say
Pick a finish line
Tell me when you want to be mortgage-free and I will work out the extra monthly payment you need.What each extra payment buys you
Every row uses your loan, your yearly extra, your lump sum and your biweekly choice. Only the monthly extra changes.Are you ahead after refinancing?
Everything you pay under the new loan, plus the balance still owed, compared with keeping your current loan. Above zero means the refinance is winning.Side by side
If the new rate were different
Rates around your offer.What the numbers say
Net worth from this money, year by year
Investments after tax on gains, minus what you still owe on the loan.Side by side
What the numbers say
Year by year
Your plan, with the original schedule on the right for comparison.Planning tool, not financial, legal or tax advice. Real loans have payment dates, escrow changes and prepayment rules that vary by lender, so check with yours before you send extra money. Investment returns are never guaranteed.
How to use the Mortgage Payoff Accelerator
See how much interest and how many years you can cut with extra payments, find out whether a refinance really pays off, and compare paying down the loan with investing the money instead.
Quick start
Your balance now, your interest rate and the years left. Use your latest mortgage statement.
Type an amount under Extra every month and watch the result change on the Payoff plan tab.
Fill in a rate and costs you were quoted and see if it pays off on the Refinance tab.
Use Prepay or invest to compare sending the extra to the loan with investing it.
Everything you type is saved in your own browser, so it is still there when you come back. Nothing is sent anywhere.
Your loan and plan
This is the box on the left, or at the top on a phone. Every tab uses these numbers.
| Field | What to enter |
|---|---|
| Loan balance now | What you still owe, from your latest statement. |
| Interest rate and years left | Your current rate and how long is left on the loan. Half years are fine, for example 24.5. |
| Extra every month | Money you add to your payment each month, over the regular amount. |
| Extra once a year | An amount paid every 12th month, such as a bonus or a tax refund. |
| One-time lump sum and its month | A single big payment, and which month number it is paid in. Month 12 means a year from now. |
| Biweekly | Tick this to pay half a payment every two weeks. That adds up to 13 full payments a year instead of 12. |
| Refinance offer | The new rate, the new loan length, the closing costs, whether the costs are added to the loan, and how long you will keep the home. |
| Investing instead | The yearly return you expect from investing, and the tax on the gains. |
Payoff plan
What your extra payments do
The top row shows the interest you save, the time you save, your new debt-free date and your regular payment. The chart shows the loan with and without your extra payments. Use the buttons above it to switch between the balance left and the interest paid so far. Hover over the chart to read any year.
- Where your money goes shows how much of everything you pay is the loan and how much is interest, before and after your plan.
- Milestones shows when you pay off half, reach a quarter left, start paying more principal than interest, and become debt-free.
- What the numbers say gives the plain summary, including how many dollars of interest you save for each extra dollar you pay.
Extra payment menu
See what each amount buys
The top box answers “I want to be mortgage-free in this many years”. Type the number of years and it tells you the extra monthly payment you need, the new total payment, and the interest you skip.
The table below shows what $50, $100, $500, $1,000 and more would do, and marks your own plan. For each row you get the new payment, how long the loan takes, the time and interest saved, and the interest saved per $1 of extra payment. The bar behind the interest column makes the biggest savings easy to spot.
Refinance
Does the new loan really pay off?
- Enter the new rate, the new loan length and the closing costs you were quoted.
- Choose whether the closing costs are paid now or added to the new loan.
- Set how long you plan to keep the home.
The verdict banner tells you in plain words if you come out ahead. The top row shows the payment change, the break-even time, the net result over your stay, and the best case along the way. The chart shows your advantage over time, and when the line crosses zero you have earned back the costs. It counts everything you pay plus the balance still owed, so the comparison is fair even when the new loan is longer.
The table on the right shows the same result for rates a little above and below your offer, which helps you decide how much a better rate is worth.
Prepay or invest
Extra loan payments or the stock market?
This tab takes your extra monthly amount and compares two paths up to the original payoff date. In the first path you prepay the loan, and once it is gone you invest the whole freed-up payment. In the second you pay the loan normally and invest the extra every month. Both are shown as net worth: investments after tax on gains, minus what you still owe.
The break-even return is the yearly return after tax where the two paths tie. If you expect the market to beat it, investing wins on paper. If not, prepaying wins, and it is guaranteed.
Yearly schedule
The year-by-year picture
One row per year shows what you pay, how much goes to principal and interest, the extra you add, and the balance at the end of the year. The original schedule’s balance is on the right so you can compare. Years after your plan pays the loan off are greyed out.
Worked example
A $380,000 loan at 6.5% with 30 years left
The regular payment is $2,402 a month. Adding $250 a month gives:
On the Extra payment menu, a goal of 20 years needs about $432 extra a month and skips $184,877 of interest. Adding $1,000 a month would finish in 14 years 4 months.
A refinance to 5.75% for 30 years with $6,000 of closing costs cuts the payment by $184 a month, breaks even after 2 years 2 months, and leaves you $13,974 ahead after 7 years.
On Prepay or invest, with a 7% return and 15% tax on gains, prepaying ends with $266,940 and investing with $262,009. The break-even return is about 7.1% a year. So at these numbers, paying down the loan is slightly ahead and has no risk.
This guide and the tool are planning tools, not financial, legal or tax advice. Real loans have payment dates, escrow changes and prepayment rules that vary by lender, so check with yours before you send extra money. Investment returns are never guaranteed.