# Mortgage Calculator API

> For the complete documentation index, see [llms.txt](/llms.txt).

Monthly payment, total interest, LTV, and optional amortization schedule.

Use this endpoint to add the tool to your app, site, workflow, or agent without rebuilding formulas, validation, examples, and docs.

- Slug: `mortgage-calculator`
- Category: `finance`
- Version: `2026-04-22`
- Credits per successful call: 5
- Starts on: pro
- Max payload: 4096 bytes
- Privacy mode: `hash_only`
- Available on: pro, business, scale
- Browser tool: https://miniwebtool.com/mortgage-calculator/

## Endpoint

`POST https://api.miniwebtool.com/v1/tools/mortgage-calculator/run`

## Request body

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `home_price` | `float` | yes |  |
| `down_payment` | `float` | yes |  |
| `annual_rate_percent` | `float` | yes |  |
| `years` | `float` | yes |  |
| `include_schedule` | `bool` | no |  |
| `property_tax_annual` | `float` | no |  |
| `home_insurance_annual` | `float` | no |  |
| `pmi_annual_percent` | `float` | no |  |

## Example request

```json
{
  "home_price": 500000,
  "down_payment": 100000,
  "annual_rate_percent": 6.5,
  "years": 30,
  "include_schedule": false,
  "property_tax_annual": 6000,
  "home_insurance_annual": 1800,
  "pmi_annual_percent": 0
}
```

## cURL

```bash
curl -X POST https://api.miniwebtool.com/v1/tools/mortgage-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"home_price":500000,"down_payment":100000,"annual_rate_percent":6.5,"years":30,"include_schedule":false,"property_tax_annual":6000,"home_insurance_annual":1800,"pmi_annual_percent":0}'
```

## Response envelope

```json
{
  "request_id": "01K...",
  "tool": "mortgage-calculator",
  "tool_version": "2026-04-22",
  "credits_used": 5,
  "result": {}
}
```

## Errors

Errors are RFC 7807 `application/problem+json`. Branch on `code`, not `title`.

## MCP

Agents can discover and call this tool through `https://api.miniwebtool.com/mcp` or `https://api.miniwebtool.com/v1/mcp` using MCP `tools/list` and `tools/call`.

## Frequently asked

### What does the Mortgage Calculator API do?

Monthly payment, total interest, LTV, and optional amortization schedule. Use it to add this utility without rebuilding formulas, validation, examples, and documentation.

### How much does one call cost?

5 credits per successful call. Failed calls do not bill.

### What parameters are required?

Required fields: home_price, down_payment, annual_rate_percent, years. Full schema at `https://api.miniwebtool.com/v1/openapi.json`.

### Is this deterministic?

Yes. Same input, same output. Tool version: 2026-04-22.