Give your loan the second look: your real payoff date, what it truly costs in interest, and exactly how much an extra payment every month buys back — in dollars and in months.
How to use it: pick your loan type, enter the balance, rate, and term, then try an extra payment — The Math shows exactly what it buys back.
Every extra dollar goes straight to principal.
Principal & interest only — mortgage figures exclude taxes, insurance, and PMI. Assumes fixed rate and no prepayment penalty. Estimates for planning, not a loan offer.
Nearly all auto loans are simple-interest: interest accrues daily on whatever the balance is that day. There's no schedule to outsmart and no penalty math to decode — every extra dollar shrinks tomorrow's balance, and tomorrow's interest is charged on the smaller number. That's the whole trick, and it's why the accelerator above moves the payoff date instead of just the last payment.
Two phrases do most of the work. When you send extra, say "apply this to principal" — some servicers otherwise treat it as an early next payment, which advances your due date and saves you nothing. And when you're ready to close the loan out, ask for a "10-day payoff quote," not your app's displayed balance: the quote includes the per-diem interest through your payment's arrival, which is why the balance on screen is always a little lower than the number that actually ends the loan.
Paying off early can also trigger refunds people forget they're owed: if GAP coverage or an extended warranty was financed into the loan, the unused portion is typically refundable when the loan ends ahead of schedule — but usually only if you ask the dealer or administrator. On a loan closed years early, that's real money sitting behind one email.
One honest comparison before you commit the cash flow: if your rate is high because of when or how you financed, refinancing might beat prepaying — a lower rate saves on every dollar, while extra payments only save on the dollars you send. Run the accelerator above, then compare it against a refi quote, and let the two interest numbers argue it out. If you're upside down from a rollover, our negative equity calculator shows what you're actually working against.
Estimates are principal and interest only. Check your loan contract for prepayment terms, and tell your lender extra payments go to principal — some default to advancing your due date instead.