Mortgage Amortization Calculator
See every payment, every month - and exactly how extra payments slash your total interest.
📊 What is a Mortgage Amortization Calculator?
A mortgage amortization calculator generates the complete payment schedule for a home loan - every payment, every month, showing exactly how much goes to interest, how much reduces your principal, and what the remaining balance is. Unlike a basic mortgage calculator that shows only the monthly payment, an amortization calculator reveals the full story of your loan from the first payment to the last.
Three situations where this tool is indispensable: first, before signing a mortgage - knowing you will pay $382,000 in interest on a $300,000 loan over 30 years helps you negotiate harder on the rate or consider a shorter term. Second, when evaluating extra payments - this calculator shows exactly how much interest an extra $200/month saves and how many years it trims from your loan, so you can make an informed decision versus investing the same money. Third, for tax preparation - the annual interest column matches your Form 1098 and tells you whether itemizing deductions is worthwhile.
Many borrowers are surprised to find that nearly 85% of their first mortgage payment goes to interest in year 1. The amortization schedule makes this concrete: on a $300,000 loan at 6.5%, month 1 interest = $1,625 and principal = $271. Month 360 interest = $12 and principal = $1,884. The schedule shows the entire journey between those two extremes.
This calculator supports both yearly and monthly schedule views. The yearly view condenses the schedule to one row per year - useful for long-range planning. The monthly view shows all 360 rows (for a 30-year loan) - useful for finding the exact month when your balance crosses 80% LTV (the PMI cancellation threshold) or verifying individual bank statements. Both views update instantly when you change any input.
📐 Formula
M = P × r × (1+r)n ÷ ((1+r)n − 1)
M = fixed monthly payment (P&I)
P = loan principal (original balance)
r = monthly rate = annual rate ÷ 12 ÷ 100
n = total payments = years × 12
Interestm = Balancem-1 × r (interest portion of each payment)
Principalm = M − Interestm (principal portion of each payment)
Balancem = Balancem-1 − Principalm
Example: $300,000 at 6.5% for 30 yrs: M = $1,896; Month 1 interest = $1,625; Month 1 principal = $271
📖 How to Use This Calculator
Generating and Reading Your Amortization Schedule
1
Enter your loan details - Type your loan principal (the amount borrowed, not the home price), annual interest rate, and loan term. Defaults pre-calculate on load so you see a schedule immediately.
2
Add an extra monthly payment (optional) - Enter any amount above the required payment you plan to make regularly. The interest saved and months cut from your loan appear in the green summary cards above the table.
3
Switch between yearly and monthly views - Click Yearly View for a condensed annual summary (great for tax planning). Click Monthly View to see every single payment - useful for finding your PMI cancellation month or verifying bank statements.
4
Find key balance milestones - In Monthly View, scan the Balance column to find the row where your balance drops below 80% of your original purchase price. That is the month you can request PMI cancellation.
5
Share or print your schedule - Use Copy Link to save a permalink with your inputs pre-filled, or Print to generate a paper copy of the full schedule for your mortgage file.
💡 Example Calculations
Example 1 — Standard 30-Year Mortgage, No Extra Payments
$300,000 loan | 6.5% interest | 30-year term | no extra payment
1
Monthly rate r = 6.5 ÷ 12 ÷ 100 = 0.005417. Total payments n = 360.
2
Monthly P&I = $300,000 × 0.005417 × (1.005417)^360 ÷ ((1.005417)^360 − 1) = $1,896/month.
3
Month 1: Interest = $300,000 × 0.005417 = $1,625; Principal = $271; Balance = $299,729. Month 12: Interest = $1,607; Principal = $289; Balance = $296,507.
4
Total paid over 30 years = $1,896 × 360 = $682,560. Total interest = $382,560 - more than the original loan amount.
Monthly payment = $1,896 | Total interest over 30 years = $382,560
Try this example →Example 2 — Same Loan with $300/Month Extra Payment
$300,000 loan | 6.5% | 30-year term | $300 extra/month
1
Required monthly payment stays $1,896. Total payment with extra = $2,196/month.
2
The extra $300 goes entirely to principal each month, reducing the balance faster and cutting future interest.
3
The loan pays off after approximately 252 months (21 years) instead of 360 months - 108 months (9 years) earlier.
4
Total interest paid ≈ $245,000. Interest saved vs. no extra payment ≈ $137,560.
Interest saved = ~$137,560 | Loan paid off 9 years early
Try this example →Example 3 — 15-Year Mortgage Comparison
$300,000 loan | 6.0% | 15-year term | no extra payment
1
Monthly rate = 0.005; n = 180. Monthly P&I = $300,000 × 0.005 × (1.005)^180 ÷ ((1.005)^180 − 1) = $2,532/month.
2
Month 1: Interest = $1,500; Principal = $1,032; Balance = $298,968. Already nearly 4× more principal than in the 30-year example.
3
Total paid = $2,532 × 180 = $455,760. Total interest = $155,760 - saving $226,800 versus the 30-year at 6.5%.
Monthly payment = $2,532 | Total interest = $155,760 (saves $226,800 vs 30-yr)
Try this example →❓ Frequently Asked Questions
What is an amortization schedule and what does it show?
An amortization schedule is a complete table listing every loan payment - showing the date, payment amount, how much goes to interest, how much reduces principal, and the remaining balance. For a 30-year mortgage, that is 360 rows. The schedule reveals that early payments are mostly interest (up to 85% in month 1) while later payments are mostly principal. It is the most transparent way to understand the full cost and structure of a loan.
Why does so much of my early mortgage payment go to interest?
Because interest is calculated on the outstanding balance. At the start, your balance equals the full loan principal - so interest is at its highest. As you pay down principal, the balance (and therefore the interest charged) falls. With a $300,000 loan at 6.5%, month 1 interest is $1,625 on a $1,896 payment - 85.7% interest. By month 180 (year 15), interest has fallen to about $1,050 per payment - still $55.4% - showing how slowly early-year principal buildup actually is.
How do I use the amortization schedule to find when I can cancel PMI?
Switch to the Monthly View and find the row where the Balance column drops to 80% of your original purchase price (not loan amount). For example, if you bought at $350,000 with $315,000 borrowed (90% LTV), PMI can be cancelled when the balance reaches $280,000 (80% of $350,000). Find that row in the monthly table - that is the month you can send a written PMI cancellation request to your lender under the Homeowners Protection Act.
How much does an extra $100/month payment save on a mortgage?
On a $300,000 30-year mortgage at 6.5%, an extra $100/month saves approximately $41,000 in total interest and cuts about 4 years from the loan. On a $200,000 loan at the same rate, an extra $100/month saves about $26,000 and shortens the term by roughly 3.5 years. Enter your exact loan details and $100 in the extra payment field for your precise savings figure.
What is the crossover point in mortgage amortization?
The crossover point is the month when the principal portion of your payment first exceeds the interest portion. For a standard 30-year mortgage, this typically occurs around month 200–220 (year 17–18). Before this point, more than half your payment goes to interest. After this point, more goes to principal. The crossover happens much earlier with a shorter term - for a 15-year mortgage it typically occurs around month 90 (year 7.5).
Can I use this schedule for my adjustable-rate mortgage?
This calculator assumes a fixed interest rate throughout the loan term. For an ARM, you can use it to model the initial fixed-rate period by setting the term equal to the fixed period (e.g., 5 years for a 5/1 ARM). To estimate the full loan with an adjustment, run a second calculation starting with the remaining balance after the fixed period at the new rate. ARMs require re-amortization at each rate adjustment, which this fixed-rate tool models accurately for one rate at a time.
How do I verify the amortization schedule against my bank statement?
Switch to Monthly View and compare each row to your monthly mortgage statement. The interest and principal split should match exactly for a standard fixed-rate loan. If your statement shows different numbers, check: (1) the exact rate - lenders sometimes quote to 3 decimal places; (2) the exact closing date - partial first month interest can shift subsequent rows; (3) whether your lender charges additional fees. The math is standardized, so any persistent discrepancy is worth querying with your servicer.
Is prepaying a mortgage always a good financial decision?
Prepayment is effectively a guaranteed, risk-free return equal to your mortgage rate. At 6.5%, prepaying is equivalent to investing in a guaranteed 6.5% annual return after-tax. Whether this beats alternatives depends on your other options. If your 401(k) match is 100%, max that first - it is a guaranteed 100% return. Pay off high-interest debt (credit cards at 20%+) before prepaying a mortgage. If you have no high-interest debt and your employer match is maxed, mortgage prepayment is an excellent risk-free use of surplus cash.
What is the total interest on a $400,000 mortgage over 30 years?
At 6.5% for 30 years: monthly payment = $2,528; total paid = $910,080; total interest = $510,080 - 127.5% of the original loan amount. At 6.0%, total interest drops to $463,529. At 7.0%, it rises to $558,034. Enter 400000, your rate, and 30 years into this calculator for the exact schedule with your current rate.
How does the loan term affect the amortization schedule?
A shorter term forces more principal into each payment, so the balance falls much faster. On a $300,000 loan at 6.5%: after 5 years, a 30-year mortgage has a balance of ~$278,000 (paid just $22K of principal); a 15-year mortgage has a balance of ~$234,000 (paid $66K of principal). The 15-year schedule also shows interest falling faster because the balance is lower each month. Compare the two schedules side-by-side by running this calculator twice with different terms.
Does making one extra mortgage payment per year significantly reduce total interest?
Yes - significantly. Making one extra full payment per year on a $300,000 30-year mortgage at 6.5% (equivalent to $158/month extra, since $1,896 ÷ 12 = $158) saves roughly $65,000 in interest and cuts about 4.5 years from the term. This is a common strategy for year-end bonuses - apply a single extra payment to principal. Model it by entering $158 in the extra monthly payment field to see the compounded annual effect.