# RC Low-Pass Filter Calculator API

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

Calculate RC low-pass cutoff, time constant, gain, attenuation and phase at a selected frequency.

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

- Slug: `rc-low-pass-filter-calculator`
- Category: `miscellaneous`
- 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

## Endpoint

`POST https://api.miniwebtool.com/v1/tools/rc-low-pass-filter-calculator/run`

## Request body

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `resistance` | `float` | no | resistance value |
| `resistance_unit` | `str` | no | ohm | kohm | mohm Choices: ohm, kohm, mohm |
| `capacitance` | `float` | no | capacitance value |
| `capacitance_unit` | `str` | no | pf | nf | uf | mf | f Choices: pf, nf, uf, mf, f |
| `frequency_hz` | `float` | no | optional evaluation frequency in hertz |

## Example request

```json
{
  "resistance": 10,
  "resistance_unit": "kohm",
  "capacitance": 100,
  "capacitance_unit": "nf",
  "frequency_hz": 100
}
```

## cURL

```bash
curl -X POST https://api.miniwebtool.com/v1/tools/rc-low-pass-filter-calculator/run \
  -H 'Authorization: Bearer mwt_live_YOUR_KEY' \
  -H 'Content-Type: application/json' \
  -d '{"resistance":10,"resistance_unit":"kohm","capacitance":100,"capacitance_unit":"nf","frequency_hz":100}'
```

## Response envelope

```json
{
  "request_id": "01K...",
  "tool": "rc-low-pass-filter-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 RC Low-Pass Filter Calculator API do?

Calculate RC low-pass cutoff, time constant, gain, attenuation and phase at a selected frequency. 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.