# Steel Weight Calculator API

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

Weight of steel and other metal bars, plates, pipes, tubes, and angles from shape dimensions, density, and quantity.

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

- Slug: `steel-weight-calculator`
- Category: `construction`
- Version: `2026-04-22`
- Credits per successful call: 1
- Starts on: free
- Max payload: 65536 bytes
- Privacy mode: `hash_only`
- Available on: free, starter, pro, business, scale
- Browser tool: https://miniwebtool.com/steel-weight-calculator/

## Endpoint

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

## Request body

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `shape` | `str` | no | round_bar | square_bar | hex_bar | flat_bar | plate | round_pipe | square_tube | rect_tube | angle Choices: round_bar, square_bar, hex_bar, flat_bar, plate, round_pipe, square_tube, rect_tube, angle |
| `material` | `str` | no | mild_steel | stainless_304 | stainless_316 | alloy_steel | tool_steel | galvanized_steel | cast_iron | aluminum | brass | copper | custom Choices: mild_steel, stainless_304, stainless_316, alloy_steel, tool_steel, galvanized_steel, cast_iron, aluminum, brass, copper, custom |
| `custom_density` | `float | None` | no | Density in kg/m^3 (material=custom) |
| `dim_a` | `float` | no | Primary dimension in mm: diameter, side, across-flats, or width |
| `dim_b` | `float | None` | no | Second dimension in mm (rect_tube, angle) |
| `thickness` | `float | None` | no | Thickness or wall in mm (flat_bar, plate, pipes, tubes, angle) |
| `length_m` | `float` | no | Length per piece in meters |
| `quantity` | `int` | no |  |
| `price_per_kg` | `float | None` | no |  |

## Example request

```json
{
  "shape": "round_bar",
  "material": "mild_steel",
  "dim_a": 20,
  "length_m": 6,
  "quantity": 10
}
```

## cURL

```bash
curl -X POST https://api.miniwebtool.com/v1/tools/steel-weight-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"shape":"round_bar","material":"mild_steel","dim_a":20,"length_m":6,"quantity":10}'
```

## Response envelope

```json
{
  "request_id": "01K...",
  "tool": "steel-weight-calculator",
  "tool_version": "2026-04-22",
  "credits_used": 1,
  "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 Steel Weight Calculator API do?

Weight of steel and other metal bars, plates, pipes, tubes, and angles from shape dimensions, density, and quantity. Use it to add this utility without rebuilding formulas, validation, examples, and documentation.

### How much does one call cost?

1 credit per successful call. Failed calls do not bill.

### What parameters are required?

Required fields: (none). Full schema at `https://api.miniwebtool.com/v1/openapi.json`.

### Is this deterministic?

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