# Percentage Calculate — REST API endpoint `percentage-calculate`

Percentage math. Modes: percent_of (a% of b), what_percent (a is what % of b), percent_change (from a to b).

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

## Call the endpoint (verified example)

```bash
curl -X POST https://api.findutils.com/api/tools/percentage-calculate/execute \
  -H "Content-Type: application/json" \
  -d '{
    "mode": "percent_of",
    "a": 20,
    "b": 50
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/percentage-calculate
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `mode` | string (percent_of \| what_percent \| percent_change) | yes | Calculation mode. |
| `a` | number | yes | First value. |
| `b` | number | yes | Second value. |

Example arguments (verified):

```json
{
  "mode": "percent_of",
  "a": 20,
  "b": 50
}
```

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:percentage_calculate`. Full MCP reference: https://findutils.com/mcp/percentage-calculate/

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