Amortization Calculator
Generate a full month-by-month payment schedule for any fixed-rate loan.
Month-by-month schedule
| # | Date | Payment | Principal | Interest | Balance |
|---|
What is amortization calculator?
An amortization schedule is the full month-by-month story of a fixed-rate loan. Each payment is the same dollar amount, but its split between principal and interest changes every month. Month 1 of a $200,000 mortgage at 6.5% sends $1,083 to interest and $181 to principal. Month 360 sends almost all of the $1,264 to principal. The crossover — when principal first exceeds interest in a single payment — happens roughly two-thirds of the way through the loan for typical rates.
The calculation is simpler than it looks. Each month: interest = balance × monthlyRate, then principal = payment − interest, then newBalance = oldBalance − principal. Repeat for n months. The monthly payment M is chosen so the balance hits zero exactly at month n — the formula M = P × r / (1 − (1 + r)^−n) is what makes it line up.
For users planning extra payments, biweekly schedules, or lump-sum prepayments, the mortgage-payoff calculator handles those scenarios. This tool stays focused on the straight schedule: enter the loan, get the table, download or print it.
When to use a amortization calculator
- Seeing how a mortgage breaks down — A homebuyer wants to see how much of their $1,264 monthly payment goes to interest vs principal in year 1 vs year 20.
- Generating a printable payment schedule — A bookkeeper needs a complete table of payments for a small business loan to attach to year-end records.
- Comparing loan offers — Two lenders quote different rates and terms. Run each through the calculator to see total interest paid over the life of the loan, not just the monthly number.
How to use the Amortization Calculator
- Enter loan amount and rate — Type the principal (the amount you're borrowing) and the annual percentage rate as quoted by the lender (6.5 means 6.5%).
- Set the term — Choose years or months and enter the loan length. A 30-year mortgage is 360 months.
- Optional: set a start date — If you want the schedule labeled with real calendar months instead of 'Month 1, Month 2, …', enter the date of your first payment.
- Review and download — Expand the month-by-month schedule to see every payment. Click 'Download CSV' to open it in a spreadsheet, or print the page for a paper schedule.
Worked examples
30-year mortgage
Input: $200,000 at 6.5%, 30 years
Output: Monthly $1,264.14, total interest $255,089, total paid $455,0895-year auto loan
Input: $25,000 at 5%, 60 months
Output: Monthly $471.78, total interest $3,307, total paid $28,307Zero-interest loan
Input: $12,000 at 0%, 12 months
Output: Monthly $1,000, total interest $0, total paid $12,000Frequently asked questions
What is amortization?
How is the monthly payment calculated?
M = P × r / (1 − (1 + r)−n), where P is the principal, r is the monthly rate (annual rate ÷ 12), and n is the term in months. This produces a constant payment that pays off the loan exactly in n months.