# Amortization Calculator — REST API endpoint `amortization-calculator`

Return a full loan amortization schedule (one row per month with payment, principal, interest, extra payment, balance) plus totals, interest saved, months saved, and the payoff month. Rate is a yearly percentage; payments are monthly.

- Category: finance
- MCP server: https://mcp.findutils.com/ (Streamable HTTP, no API keys, 120 req/min per IP)
- REST endpoint: POST https://api.findutils.com/api/tools/amortization-calculator/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/api/amortization-calculator/
- Same tool on the other surface: https://findutils.com/mcp/amortization-calculator/

## Call the endpoint (verified example)

```bash
curl -X POST https://api.findutils.com/api/tools/amortization-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "loan_amount": 250000,
    "interest_rate": 6.5,
    "loan_term_years": 30,
    "start_month": "2026-01"
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/amortization-calculator
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `loan_amount` | number | yes | Loan principal. |
| `interest_rate` | number | yes | Yearly interest rate in percent (6.5 = 6.5%). Must be > 0. |
| `loan_term_years` | integer | yes | Loan term in years (1-40). |
| `extra_payment` | number | no | Optional extra principal paid every month. Default: 0. |
| `start_month` | string | no | First payment month as YYYY-MM. Default: the current UTC month. |

Example arguments (verified):

```json
{
  "loan_amount": 250000,
  "interest_rate": 6.5,
  "loan_term_years": 30,
  "start_month": "2026-01"
}
```

OpenAPI 3.1 spec: https://findutils.com/api/openapi.json · Interactive docs: https://findutils.com/api/docs/

## Also an MCP tool

```bash
claude mcp add findutils --transport http https://mcp.findutils.com/
```

Then ask the client to call `findutils:amortization_calculator`. Full MCP reference: https://findutils.com/mcp/amortization-calculator/

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