calc.engineer / General & Math / Loan Amortization

Loan Amortization v1.0.0

Computes a full loan amortization schedule given principal, annual interest rate, and term in months. Returns the fixed monthly payment, total interest, total payments, and a month-by-month breakdown of principal vs interest. Supports optional extra monthly payments — shows months saved and interest saved. Works for mortgages (30yr/15yr), auto loans, personal loans, and student loans. All currency-agnostic. Use with /run?page=1&page_size=12 to paginate the schedule array for context-friendly agent consumption.

Loan principal amount in dollars (or any currency unit).
Annual interest rate as a percentage (e.g., 6.5 for 6.5%).
Loan term in months. Max 600 (50 years). Common values: 360 (30yr), 180 (15yr), 60 (5yr auto).
Optional fixed extra monthly payment toward principal. Defaults to 0.
Fill in the inputs and Compute to see the structured result.

From an agent (MCP) or the API

curl -X POST https://calc.engineer/api/loan_amortization \
  -H "Content-Type: application/json" \
  -d '{"principal": …, "annual_rate_pct": …, "term_months": …}'

MCP: connect to https://calc.engineer/mcp and call loan_amortization.

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