What Is an Amortization Schedule?
An amortization schedule is the complete table of every payment on an installment loan, showing how each one splits between interest(the lender's charge on your remaining balance) and principal (the part that actually pays the loan down). The monthly payment stays the same; the split shifts every month — interest-heavy at the start, principal-heavy near the end.
Mortgages, auto loans, personal loans, and student loans all follow this structure. The schedule above generates it for any fixed-rate loan, month by month, with optional extra payments.
The Amortization Formula
Every schedule starts from one formula that computes the level monthly payment M for principal P, monthly rate i (annual rate ÷ 12), and n payments:
Then each month repeats two lines: interest = balance × i, and principal = M − interest(plus any extra), with the balance dropping by that principal. That's the whole algorithm — the table is just those two lines repeated to zero. Our loan interest guide walks the same arithmetic step by step.
Worked Example: $300,000 at 6.5% for 30 Years
The reference numbers this site uses across its mortgage guides:
- Monthly payment: $1,896.20 (payment 1 above)
- Payment 1: $1,625.00 interest + $271.20 principal — 86% of it is interest
- Year 1 total: $19,401 interest vs only $3,353 principal
- Balance after 5 years of payments: $280,833 — you've paid $113,772 to reduce the debt by just $19,167
- Total interest over 30 years: $382,633 on a $300,000 loan
Those first-years numbers are the amortization shock most borrowers never see until they look at a schedule like the one above — which is exactly why lenders must provide one at closing.
The Crossover Point
Somewhere mid-schedule, the principal share of each payment overtakes the interest share. On the $300,000/6.5% loan that happens at payment 233 — year 19. Shorter terms and lower rates pull the crossover dramatically earlier: on a 15-year loan at the same balance, principal beats interest in the very first payment. Scan any column of the table above and you can find your own crossover in seconds.
How Extra Payments Rewrite the Table
Extra principal doesn't just subtract from the last row — it recomputes everything after it. Pay $200 extra once and your balance is permanently $200 lower, so everysubsequent month's interest line shrinks a little, which moves more of each fixed payment to principal, compounding for the rest of the term. Enter +$200 in the calculator: on the reference loan the payoff falls from 360 payments to 277 (23y 1m) and total interest drops by $103,449. The pay off your mortgage faster guide ranks all the strategies built on this mechanism.
FAQs
What is an amortization schedule?
A complete table of every payment on an installment loan, showing how each payment splits between interest (the lender's charge on your remaining balance) and principal (the amount that actually reduces the loan). The payment total stays level while the split shifts: interest-heavy in the early years, principal-heavy near the end. Mortgages, auto loans, personal loans, and student loans all amortize this way.
How do I calculate my monthly loan payment?
For principal P, monthly rate i (annual rate divided by 12), and n payments, the payment is M = P × i × (1+i)^n / ((1+i)^n − 1). For a $300,000 30-year loan at 6.5%, that gives $1,896.20 per month. The calculator above applies this formula and then walks the schedule month by month.
When does principal exceed interest on a 30-year mortgage?
On a $300,000 30-year loan at 6.5%, the crossover arrives at payment 233 — about year 19. Before that, the interest share of each payment is larger than the principal share; after it, principal takes over and the balance falls faster. On 15-year loans the crossover often happens in the very first payment. Scan the interest and principal columns above to find your own crossover year.
How do extra payments change my amortization schedule?
Extra principal lowers the balance immediately, which cuts the interest portion of every later payment and shifts more of each fixed payment to principal. On the $300,000 30-year 6.5% reference loan, adding $200 a month pays it off in 23 years 1 month instead of 30 and saves $103,449 in interest. Enter any extra amount above and the table rebuilds with the new payoff point.
Will this schedule match my lender's exactly?
Very closely, but not to the penny. Servicers round differently, accrue interest on slightly different conventions, and set first-payment dates that shift the initial month. Use this table to understand the shape of your loan and compare strategies; rely on your lender's official amortization disclosure for the binding numbers.
Estimates for fixed-rate amortized loans. Adjustable-rate loans, fees, and rounding at your servicer will shift real schedules slightly.