Amortization
Amortization is the process of paying off a loan in equal scheduled payments over time, where each payment combines principal and interest. Early in the loan, most of each payment goes to interest; late in the loan, most goes to principal. The full payment-by-payment breakdown is called an amortization schedule.
Amortization is what makes installment loans predictable. The lender calculates a fixed monthly payment that, if made on schedule for the full term, exactly repays the principal plus all interest accrued. Each individual payment is split between interest (calculated on the outstanding balance for that period) and principal (whatever’s left after the interest portion).
The front-loaded interest pattern
On any amortizing loan, early payments are interest-heavy and late payments are principal-heavy. This is because interest accrues on the outstanding balance: which is largest at the start and smallest at the end.
A $1,000 loan at 36% APR over 12 months has monthly payments around $100. The first payment is roughly $30 interest and $70 principal. The last payment is roughly $3 interest and $97 principal. Same total payment, very different splits.
Why this matters for early payoff
Because so much interest accrues in the early months, paying off an amortizing loan early saves significantly more interest than the simple “X months remaining” math suggests. Most personal installment loans have no prepayment penalty and many states require lenders to refund unearned interest on early payoff. Check your loan agreement.
You can see the exact amortization schedule for any loan using our loan repayment calculator.