# Refinance Calculator — REST API endpoint `refinance-calculator`

Return the new monthly payment, monthly savings, total cost of the current vs the new loan, total savings, break-even month, and whether a mortgage refinance is worth it. Closing costs are added to the new loan balance. Rates are yearly percentages. Give current_monthly_payment, or give current_rate and it is computed from the balance and the remaining months.

- 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/refinance-calculator/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/api/refinance-calculator/
- Same tool on the other surface: https://findutils.com/mcp/refinance-calculator/

## Call the endpoint (verified example)

```bash
curl -X POST https://api.findutils.com/api/tools/refinance-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "current_balance": 250000,
    "current_monthly_payment": 1580,
    "remaining_months": 300,
    "new_rate": 5.5,
    "new_term_months": 360,
    "closing_costs": 5000
  }'

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

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `current_balance` | number | yes | Remaining balance on the current loan. Must be > 0. |
| `current_monthly_payment` | number | no | Current monthly payment. Optional when current_rate is given. |
| `current_rate` | number | no | Current yearly rate in percent. Used only to compute a missing current_monthly_payment. |
| `remaining_months` | integer | yes | Months left on the current loan. |
| `new_rate` | number | yes | New yearly rate in percent. |
| `new_term_months` | integer | yes | New loan term in months (360 = 30 years). |
| `closing_costs` | number | no | Refinance closing costs. Default: 0. |

Example arguments (verified):

```json
{
  "current_balance": 250000,
  "current_monthly_payment": 1580,
  "remaining_months": 300,
  "new_rate": 5.5,
  "new_term_months": 360,
  "closing_costs": 5000
}
```

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:refinance_calculator`. Full MCP reference: https://findutils.com/mcp/refinance-calculator/

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