Quick answer
How do you calculate Mortgage Amortization?
Use Payment = Principal x [r(1 + r)^n] / [(1 + r)^n - 1]. Enter the matching values above to calculate the result instantly.
What it measures
Understanding Mortgage Amortization
Calculate a fixed mortgage payment and the total principal, interest, and number of payments across the loan term. Amortization keeps the scheduled payment level while changing its composition: early payments contain more interest and later payments contain more principal. Total interest can exceed the original balance on long, higher-rate loans, which makes term and rate comparisons as important as the monthly payment.
Interpretation
What the result means
The primary result is principal and interest only. The supporting outputs show the total amount paid and the financing cost if every scheduled payment is made and the rate never changes.
Action
How to use it
Compare terms using both monthly cash flow and total interest. If considering extra principal payments, confirm how the servicer applies them and whether any prepayment restrictions or recast options exist.
Limits
What it leaves out
The calculation excludes tax, insurance, HOA dues, mortgage insurance, fees, points, skipped payments, extra payments, variable rates, and rounding practices used by a specific lender.
The math
Mortgage Amortization formula
Worked example
Example calculation
- Calculation
- $360,000 amortized across 360 monthly payments at 6.5%
- Result
- About $2,275 per month and $459,000 of total interest
Step by step
How to use this calculator
- 1Enter mortgage amount, annual interest rate, loan term in years.
- 2Keep every input on the same time period and measurement basis.
- 3Review the result, then change one assumption at a time to test scenarios.
Decision support
When this calculator is useful
- Comparing 15- and 30-year mortgages
- Estimating lifetime interest
- Understanding loan amortization
Common questions
Frequently asked questions
Which inputs should I use for Mortgage Amortization?
Use mortgage amount, annual interest rate, loan term in years, measured from the same source and period. Include only values that match the definitions shown beside each field.
Why might two Mortgage Amortization calculations differ?
The systems or accounting policies may define mortgage amount, annual interest rate, loan term in years differently. Compare the time period, scope, source, and treatment of exceptional items before comparing results.
How often should I recalculate Mortgage Amortization?
Recalculate when any input changes materially and on the same reporting cadence used for the decision. Save the source and date of each input so the trend remains comparable.
Can I use Mortgage Amortization by itself?
No single metric captures the full decision. Use the result with the related measures, assumptions, and limitations shown on this page.
Calculation reviewed: 2026-06-18. CalcPilot uses the formula shown above and tests representative values during the production build. See our methodology and correction policy.
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