What this page sets up
The calculator opens for a line you already have: 60,000 owed, 5 interest-only years left in the draw period, then 20 years of repayment, with 250 extra each month. Replace the numbers with your own statement: Balance owed now is the current balance, Draw years left the years until the draw period ends, and Repayment years the length of the repayment period. If you’re already repaying, set Draw years left to 0 and Repayment years to the years left in it, not its full length: 45,000 with 15 of 20 years to go is 417.16 a month over 15 years, not 362.52 over 20. The rate is prime plus the margin in your agreement.
The large figure is when the balance is paid off with your extra payment, and the line under it the total interest from now on.
Reading the result
The notice under the payments says how much sooner the extra payment clears the balance and how much interest it saves. The table Extra payments vs payoff time runs the same line with no extra and with 100, 250, 500 and 1,000 a month, your own amount highlighted, so you can see where more money stops making a big difference. Owed when repayment starts shows the balance your repayment payment will be based on, and a payment shock line appears only if the payment still jumps when repayment starts. In the example, 250 a month for 5 years brings the 60,000 down to 45,000 before repayment begins, which takes a quarter off the repayment payment.
Making a payoff plan
- Make sure the extra goes to principal. Ask how the lender applies payments above the minimum, and whether the plan charges anything for overpaying.
- Don’t draw again while you pay down, or the plan starts over. Freezing or lowering the limit can help.
- Watch the rate. A HELOC’s rate moves with prime. The scenarios under the results show the payoff cost if it rises.
- Compare a fixed loan. If the repayment payment is the worry, ask whether your plan can convert the balance to a fixed-term loan; the home equity loan page shows what a fixed payment would be.
To see how any lump sum you put aside would grow instead, the interest calculator works it out with deposits.
Extra payments during the draw period
$60,000 owed at 7.50% (prime 7.00% on September 21, 2026 plus a 0.5-point margin), 5 interest-only years left, then 20 years of repayment. Every extra dollar in the draw period lowers the balance the repayment payment is worked out on:
| Extra a month | Owed when repayment starts | Repayment payment | Paid off after | Total interest | Interest saved |
|---|---|---|---|---|---|
| None | $60,000.00 | $483.36 | 25 yr | $78,505.42 | – |
| $100 | $54,000.00 | $435.02 | 18 yr 4 mo | $52,960.64 | $25,544.78 |
| $250 | $45,000.00 | $362.52 | 13 yr 3 mo | $35,160.43 | $43,344.99 |
| $500 | $30,000.00 | $241.68 | 8 yr 11 mo | $21,660.58 | $56,844.84 |
| $1,000 | $0.00 | Paid off | 5 yr | $11,437.50 | $67,067.92 |
Extra payments once repayment has started
$45,000 owed at the same rate with 15 years of repayment left, where the required payment already includes principal:
| Extra a month | Total a month | Paid off after | Total interest | Interest saved | Time saved |
|---|---|---|---|---|---|
| None | $417.16 | 15 yr | $30,088.00 | – | – |
| $100 | $517.16 | 10 yr 6 mo | $20,150.25 | $9,937.75 | 4 yr 6 mo |
| $250 | $667.16 | 7 yr 4 mo | $13,618.08 | $16,469.92 | 7 yr 8 mo |
| $500 | $917.16 | 4 yr 11 mo | $8,910.21 | $21,177.79 | 10 yr 1 mo |
Worked out month by month with the calculator's own engine: interest is the annual rate ÷ 12 on the balance, and the rate is held at today's for the whole term. Sources: Federal Reserve H.15 via FRED, bank prime loan rate; CFPB, What you should know about home equity lines of credit. For planning, not financial advice.