Amortization Schedule Calculator

An amortization schedule is a complete table of every loan payment over the life of your mortgage:

Each row in the schedule shows:

• Payment number or date — which month you're paying
• Total payment amount — your fixed monthly payment
• Principal portion — how much reduces your loan balance
• Interest portion — the interest charge for that month
• Remaining balance — what you still owe after this payment

Example: $320,000 at 6.75% for 30 years

• Month 1: Payment $2,076 — Interest $1,800 — Principal $276 — Balance $319,724
• Month 12: Payment $2,076 — Interest $1,784 — Principal $292 — Balance $316,559
• Month 180 (Year 15): Payment $2,076 — Interest $1,341 — Principal $735 — Balance $237,892
• Month 360 (Year 30): Payment $2,076 — Interest $12 — Principal $2,064 — Balance $0

This calculator generates both a yearly summary (grouped by year) and the full month-by-month table, which you can download as a CSV file for use in Excel or Google Sheets.

Each monthly payment is split between interest and principal using a simple formula:

• Monthly interest = Remaining balance × (Annual rate ÷ 12)
• Principal payment = Total payment − Interest portion
• New balance = Old balance − Principal paid

Month 1 on a $320,000 loan at 6.75%:

• Interest: $320,000 × (6.75% ÷ 12) = $1,800
• Principal: $2,076 − $1,800 = $276
• New balance: $319,724

Month 2:

• Interest: $319,724 × (6.75% ÷ 12) = $1,798 (slightly less)
• Principal: $2,076 − $1,798 = $278 (slightly more)

Each month, a tiny bit more goes to principal and less to interest. This continues for 360 months until the final payment is almost entirely principal. The total interest paid on this loan is $427,360 — more than the original $320,000 borrowed.

It's simple — just click the green "Download CSV" button in the Amortization Schedule section:

1. Enter your loan amount, rate, and term above
2. Click "Generate Amortization Schedule" (or it calculates automatically)
3. Scroll to the Amortization Schedule section in the results
4. Click the green Download CSV button
5. A file called amortization-schedule.csv will download to your device

What's included in the CSV:

• Every monthly payment (up to 360 rows for a 30-year loan)
• Payment number, payment date (if entered), and total payment amount
• Principal paid, interest paid, and remaining balance for each month
• Cumulative interest paid to date

How to use the CSV:

• Open in Microsoft Excel, Google Sheets, or Apple Numbers
• Track your actual payments against the schedule
• Add your own columns for property taxes, insurance, or extra payments
• Share with a financial advisor, accountant, or co-borrower

Extra payments have a dramatic compounding effect, especially in the early years:

$320,000 loan at 6.75%, 30 years (base payment: $2,076/month):

Extra $100/month:

• Payoff: 26.2 years (3.8 years early)
• Interest saved: ~$59,000

Extra $200/month:

• Payoff: 23.3 years (6.7 years early)
• Interest saved: ~$107,000

Extra $500/month:

• Payoff: 18.4 years (11.6 years early)
• Interest saved: ~$202,000

Extra $1,000/month:

• Payoff: 13.4 years (16.6 years early)
• Interest saved: ~$274,000

Why early extra payments save the most:

• $1 extra in Year 1 saves approximately $2.40 in future interest
• $1 extra in Year 20 saves only about $0.40
• Early payments reduce the balance that accrues interest for decades

Enter any extra payment amount in this calculator to see the precise savings on your specific loan.

Full comparison on a $320,000 loan:

30-year at 6.75%:

• Monthly payment: $2,076
• Total interest: $427,000
• Total paid: $747,000

15-year at 6.00% (15-yr rates are typically 0.5–0.75% lower):

• Monthly payment: $2,700
• Total interest: $166,000
• Total paid: $486,000
• Interest saved: $261,000

Choose 15-year if:

• The higher payment is under 25% of gross income
• You have a 6-month emergency fund
• You have no high-interest debt
• You want to build equity fast and retire debt-free sooner

Choose 30-year if:

• You need lower required monthly payments for flexibility
• You plan to invest the payment difference (need 7%+ returns to beat it)
• You have uncertain income or high other expenses

The compromise strategy: Get a 30-year mortgage but make 15-year-sized payments voluntarily. You get the security of a lower required payment but still pay off in roughly 15 years — and can reduce payments if finances tighten.

Refinancing resets your amortization clock — timing is everything:

Best time: Years 1–10

• You're paying mostly interest anyway — a lower rate saves the most
• Closing costs break even faster (usually 1–3 years)
• Remaining loan term is long, maximizing savings

Still worth it: Years 10–20

• Refinance to a shorter term, not back to 30 years
• Example: At year 10 with 20 years left, refinance into a 15-year, not a new 30-year
• Rate drop should be at least 1% to justify closing costs

Rarely makes sense: Years 20+

• Most of each payment is already principal — little interest left to save
• Closing costs ($3K–$8K) likely exceed remaining interest savings
• You're in the home stretch — keep going

The refinance rule of thumb:

• Monthly savings × Months you'll stay = Total savings
• Total savings must exceed closing costs
• Example: Save $200/month, closing costs $5,000 — break even in 25 months
• If staying 3+ more years: refinance probably makes sense

Critical mistake to avoid: Refinancing Year 10 of a 30-year into a new 30-year. You had 20 years left, now you have 30. Monthly payment drops, but you pay far more total interest. Always refinance to a term no longer than your remaining balance.

The equity crossover is when more of each payment goes to principal than to interest.

On a 30-year loan at 6.75%, this happens around Month 218 — Year 18. For the first 17+ years, interest receives the larger share of every payment. After Year 18, principal gets more.

Why it matters:

• Before crossover: You're mostly renting money from the bank
• After crossover: You're rapidly building equity in your home
• Refinancing before crossover has less impact on equity-building pace

How extra payments move the crossover earlier:

• $100/month extra → crossover at approximately Month 196 (Year 16)
• $200/month extra → crossover at approximately Month 178 (Year 15)
• $500/month extra → crossover at approximately Month 144 (Year 12)

Check the monthly schedule in this calculator to find the exact month where the Principal column first exceeds the Interest column for your specific loan.