Home Refinance calculator
Refinance calculator
Take the prepayment fee off the interest you drop and see what is left.
Change the balance, rates, term, or fee and the net save updates at once. Moving 300000000 from 5% to 3.5% leaves a monthly gap of 261088 and a net save of 89238538.
Net save
89,238,538
89,238,538 · 261,088 · 7
- Monthly now
- 1,634,581
- Monthly after
- 1,373,493
- Prepayment fee
- 1,120,000
- Break-even
- 7
| Interest now | 268,834,156 |
|---|---|
| Interest after | 177,975,618 |
| Fee and other costs | 1,620,000 |
Why this exists
This page compares keeping the remaining loan with switching the same balance to a new rate and a new term. A level monthly payment is the annuity rounded to a whole unit. Total interest is the unrounded annuity times the term, rounded once, then minus principal, so a few units can sit between monthly times months and the interest line.
The prepayment fee is the balance times the fee rate times the share of a three-year window still left. Elapsed months are the original term minus the months left, and the window is the shorter of 36 and the original term. Twelve months elapsed leave 24 of 36, so 300000000 × 0.56% × 24/36 = 1120000. After the window has passed, the fee is 0 no matter what rate you type.
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01How to use it
Break-even is the fee plus other costs divided by the monthly gap, rounded up. 1120000 plus 500000 is 1620000, and 1620000 / 261088 is 6.20, so 7 months. With the fee at 0 only 500000 remains, which is 2 months.
The methods are a level payment, equal principal, and a bullet. On 100000000 for 120 months at 6%, the level payment is 1110205 every month, equal principal starts at 1333333 and ends at 837500, and the bullet pays interest of 500000 each month and 100500000 at the end.
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02What you get
The large figure is the net save. Under it are the monthly payment now, the monthly payment after, the fee, and the break-even. The table holds both interest totals and the costs.
5% to 3.5%, Fee 0, Equal principal, and Bullet jump to those cases. Home 0.56% and Credit 0.11% are the fee rates often written after 2025-01-13. The rate in your own contract goes in the field.
Entered5% to 3.5%
Monthly now 1634581 Monthly after 1373493 Fee 1120000 Net save 89238538 -
03Worth knowing
A longer new term can lower the monthly payment while total interest rises. The same 300000000 at 3.5% for 600 months pays 1059601 a month, but interest is 335760344, above the current 268834156, so the net save is negative.
The page does not guess a future variable-rate path. It uses only the fee rate you type, and the bank sets the real fee and the real rate. When the interest gap is smaller than the fee plus other costs, the net save is negative and shows a loss.
Questions
- QIs this figure a promised save?
- ANo. It is the gap at the rate and the fee you typed. The bank sets the real terms.
- QHow does the fee shrink?
- AElapsed months drop out of the three-year window. After 12 months, 24/36 remains and the fee is 1120000.
- QIs a longer term always a gain?
- ANo. Stretched to 600 months the payment falls to 1059601, but interest of 335760344 is higher than now.
- QHow do the three methods differ?
- AA level payment stays flat, equal principal keeps the principal slice flat so later payments shrink, and a bullet pays interest until the last payment adds the balance.
How this page works it out
Refinance compares paying the remaining balance at the current rate for the months left with paying it at a new rate. A level monthly payment rounds the annuity to a whole unit. Total interest multiplies the unrounded annuity by the term, rounds once, and subtracts principal.
A balance of 300000000, 348 months left on an original 360, from 5% to 3.5%, a fee rate of 0.56%, and other costs of 500000 move the monthly payment from 1634581 to 1373493, a gap of 261088. Interest falls from 268834156 to 177975618, and after the fee of 1120000 left once 12 months have passed the net save is 89238538. With the fee at 0 it is 90358538.
The fee keeps only the share of the three-year window that is left. Stretching the new term to 600 months lowers the payment to 1059601, but interest of 335760344 is higher than now, so the net save turns negative. On 100000000 for 120 months at 6% the level payment is 1110205, equal principal starts at 1333333, and a bullet ends at 100500000. Level interest is 33224602, equal-principal interest is 30250000 and its last payment is 837500, and bullet interest is 60000000.