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| Year | Payment | Principal | Interest | Remaining balance |
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A car loan pays down through equal fixed payments, with the interest-versus-principal split inside each one moving every month even while the payment amount holds steady.
On a $30,000 loan, the very first payment is calculated on the full $30,000 balance, so most of it is interest by definition. Once a few thousand dollars of principal come off, the same fixed payment recalculates against a smaller number and less of it goes to interest. Car loans clear this effect faster than mortgages because five years of payments erode a balance much quicker than thirty years does.
Yes, and the saving comes from time rather than from the rate. Every extra dollar goes straight to principal, so interest for every later month is charged on a smaller balance.
On $30,000 at 7% over five years the scheduled payment is $594.04 and total interest is $5,642. Adding $50 a month clears the loan in 55 months instead of 60 and drops total interest to $5,110, a saving of $533. The car loan calculator here does not model extra payments; the student loan calculator does.
Amortization is how a fixed-payment loan pays down over time: each payment covers the interest owed on the remaining balance plus a portion of principal, with the split between the two shifting every month even though the total payment stays constant.
Early payments are mostly interest relative to principal, because interest accrues on the outstanding balance, which is largest at the start of the loan. As you pay down principal, less interest accrues each month, so a growing share of every fixed payment chips away at the balance instead.
The payment formula is: payment = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where P is the amount financed, r is the monthly interest rate, and n is the loan term in months. Car loans typically amortize faster than mortgages simply because the terms are much shorter (3 to 7 years instead of 15 to 30), so the interest-heavy early period is compressed into a much smaller window.