Amortization Schedule Calculator
Generate a complete month-by-month or year-by-year loan amortization table showing exactly how each payment is split between principal and interest — with optional extra payment analysis.
Applied entirely to principal each month.
Understanding Your Amortization Schedule
An amortization schedule is a complete table of every loan payment, showing exactly how much goes toward interest and how much reduces your principal balance.
Why So Much Goes to Interest Early
In a standard fixed-rate mortgage, each payment is the same dollar amount — but the split between principal and interest shifts dramatically over time. Early payments are overwhelmingly interest because the balance is highest; as the balance shrinks, the interest portion shrinks with it.
Example on a $300,000 loan at 7% for 30 years:
- Month 1: ~$1,750 interest / ~$245 principal
- Month 180 (year 15): ~$1,275 interest / ~$720 principal
- Month 360 (final): ~$13 interest / ~$1,982 principal
This is why extra payments made early in a loan have the greatest impact — they eliminate future interest charges on that principal.
The Power of Extra Payments
Adding even a small extra payment each month directly reduces your balance and cuts future interest charges. The earlier you start, the greater the effect.
| Extra Payment | Interest Saved (30-yr, $300k, 7%) | Years Saved |
|---|---|---|
| $0 | Baseline | — |
| $100/mo | ~$27,000 | ~3.5 years |
| $250/mo | ~$57,000 | ~7 years |
| $500/mo | ~$96,000 | ~11 years |
Amortization vs. Interest-Only Loans
A standard amortizing loan pays down principal every month. An interest-only loan requires no principal paydown during the interest-only period — your balance stays the same. After the interest-only period ends, payments jump significantly to repay the principal over the remaining term.
Frequently Asked Questions
Can I use this for auto loans, student loans, or personal loans?
Yes — the amortization math is identical for any fixed-rate installment loan. Just enter the loan amount, rate, and term.
What does "fully amortized" mean?
A fully amortized loan is completely paid off at the end of the term with no balloon payment. All standard fixed-rate mortgages are fully amortized.
Why is there a small rounding difference in the final payment?
Amortization involves compounding arithmetic that accumulates small rounding differences. The final payment is usually a few cents different than the rest.
