Extra Payment Calculator
Every extra dollar you pay goes straight to principal, which shrinks the balance interest is charged on. Even a modest amount each month can cut years off the loan and save tens of thousands in interest. Add an extra payment below and the calculator shows the exact interest and time you save.
Your numbers
Loan balance over time
Nothing is saved or sent. The share link holds your numbers, in your browser only.
Amortization schedule
Every payment, split into principal and interest. Export it or print a copy.
| Year | Principal | Interest | Balance |
|---|---|---|---|
| 2026 | $3,000 | $11,794 | $317,000 |
| 2027 | $6,342 | $23,246 | $310,659 |
| 2028 | $6,827 | $22,760 | $303,832 |
| 2029 | $7,350 | $22,238 | $296,482 |
| 2030 | $7,913 | $21,675 | $288,569 |
| 2031 | $8,518 | $21,069 | $280,051 |
| 2032 | $9,170 | $20,417 | $270,881 |
| 2033 | $9,873 | $19,715 | $261,008 |
| 2034 | $10,628 | $18,959 | $250,380 |
| 2035 | $11,442 | $18,145 | $238,937 |
| 2036 | $12,318 | $17,269 | $226,619 |
| 2037 | $13,261 | $16,326 | $213,358 |
| 2038 | $14,277 | $15,311 | $199,081 |
| 2039 | $15,370 | $14,218 | $183,711 |
| 2040 | $16,546 | $13,041 | $167,165 |
| 2041 | $17,813 | $11,774 | $149,351 |
| 2042 | $19,177 | $10,410 | $130,174 |
| 2043 | $20,645 | $8,942 | $109,529 |
| 2044 | $22,226 | $7,361 | $87,303 |
| 2045 | $23,928 | $5,660 | $63,375 |
| 2046 | $25,760 | $3,828 | $37,616 |
| 2047 | $27,732 | $1,856 | $9,884 |
| 2048 | $9,884 | $156 | $0 |
Extra principal compounds in your favour
Interest each month is your balance times the monthly rate. Pay a little extra and the balance drops faster, so next month's interest is smaller, so even more of your regular payment attacks principal. That feedback loop is why a steady extra payment early in the loan is so powerful, and why the savings are largest when you start soon.
The green figure above shows your interest saved and how many years you shave off. Try $100, $250, and $500 a month to see how the payoff date moves.
Monthly, yearly, or one lump sum
There is no wrong way to do it. A fixed amount each month is the simplest. A yearly lump from a tax refund or bonus works too. A single one-time payment early in the loan has an outsized effect because it removes interest for every remaining month. The calculator handles all three, so you can model whatever fits your cash flow.