Documentation sections

Inductance Unit Converter

POSThttps://rftools.io/api/py/v1/calculate

Slug inductance-units. Convert inductance units instantly — henries (H), millihenries (mH), microhenries (µH), nanohenries (nH), and picohenries (pH). Essential for RF coil design, power converter inductors, and EMC filter components. Free online inductance unit converter.

Inputs

Send every one of these in inputs, in the units shown. Most are required: a call without one is refused (400) and costs nothing; one the calculator can do without takes the default shown. An input outside its range is still computed and flagged in the provenance.

Inputs of inductance-units
Name	Unit	Range	Default	Description
henrynumber	H	at least 0	0.000001	Inductance

Outputs

Returned in values, by key. A value that is unbounded or undefined is null.

Outputs of inductance-units
Field	Unit	Description
millihenry	mH	Millihenries
microhenryheadline	μH	Microhenries
nanohenry	nH	Nanohenries
picohenry	pH	Picohenries

Calling it

Calculate: one call, the request and response in full, and its errors.
Batch: this calculator with others, or a sweep, in one request.
Solve for a target: the value of one input that brings an output to a target.

curl -X POST https://rftools.io/api/py/v1/calculate \
  -H "X-API-Key: $RFTOOLS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "slug": "inductance-units",
    "inputs": {
      "henry": 0.000001
    }
  }'

import rftools

client = rftools.Client()  # reads RFTOOLS_API_KEY, or the key `rftools login` saved

result = client.calculate("inductance-units", {"henry": 0.000001})
print(result.values)
print(result.warnings, result.provenance.formula_ref)

const response = await fetch("https://rftools.io/api/py/v1/calculate", {
  method: "POST",
  headers: {
    "X-API-Key": process.env.RFTOOLS_API_KEY,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
    "slug": "inductance-units",
    "inputs": {
      "henry": 0.000001
    }
  }),
});
console.log(response.status, await response.json());

package main

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"os"
)

func main() {
	body := []byte(`{
	  "slug": "inductance-units",
	  "inputs": {
	    "henry": 0.000001
	  }
	}`)
	req, err := http.NewRequest("POST", "https://rftools.io/api/py/v1/calculate", bytes.NewReader(body))
	if err != nil {
		panic(err)
	}
	req.Header.Set("X-API-Key", os.Getenv("RFTOOLS_API_KEY"))
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		panic(err)
	}
	defer res.Body.Close()
	out, _ := io.ReadAll(res.Body)
	fmt.Println(res.Status, string(out))
}

application/json

{
  "slug": "inductance-units",
  "values": {
    "millihenry": 0.001,
    "microhenry": 1,
    "nanohenry": 1000,
    "picohenry": 1000000
  },
  "warnings": [],
  "errors": [],
  "provenance": {
    "method": "calculator:inductance-units",
    "version": "api@3f2c1a9b04de",
    "formulaRef": null,
    "assumptions": [],
    "validRange": {
      "status": "inside",
      "bounds": {
        "henry": {
          "min": 0,
          "max": null,
          "unit": "H"
        }
      },
      "outside": [],
      "model": null
    },
    "computedAt": "2026-09-24T14:05:11.003Z",
    "inputs": {
      "henry": 0.000001
    },
    "seed": null,
    "elapsedSeconds": 0.003
  }
}

{
  "detail": [
    {
      "type": "float_parsing",
      "loc": [
        "body",
        "inputs",
        "henry"
      ],
      "msg": "Input should be a valid number, unable to parse string as a number",
      "input": "abc"
    }
  ]
}

An input sent as text. Nothing was counted.

{
  "detail": "More than 120 requests in 60 seconds from this address.",
  "errorKind": "rate_limited",
  "limit": 120,
  "windowSeconds": 60,
  "upgradeUrl": "https://rftools.io/pricing/"
}

Too many requests in a minute, with Retry-After.

Same inputs on the calculator pageInductance Unit Converter, at these values