ForHosting KIT · Developer Utilities

Capacitance to capacitor code calculator

Small ceramic capacitors often have room for only three digits, so their printed marking expresses a value in picofarads rather than spelling out a unit.

● BetaFree · in your browser

Run — free How it works & API

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This calculator converts a capacitance such as 100 nF, 4.7 nF, or 22 pF into that standard code. It also shows the significant digits, multiplier, normalized value, and full picofarad interpretation, making the result easy to check before selecting, sorting, documenting, or assembling a component.

How the three-digit capacitor marking works

A standard three-digit ceramic capacitor code is read in picofarads. The first two characters form the significant number, and the third character tells you how many zeros to append. For example, 104 means 10 followed by four zeros in picofarads, which is 100,000 pF, 100 nF, or 0.1 uF. Likewise, 472 means 47 followed by two zeros, giving 4,700 pF or 4.7 nF. This calculator performs the reverse operation: you enter the capacitance and receive the marking that belongs on the part or in a component list. Units are required so that a bare number cannot be mistaken for picofarads, nanofarads, or microfarads. You may enter pF, nF, uF, either common micro symbol, mF, or F. Spaces are optional, and scientific notation is accepted when the resulting value is finite and positive. The returned interpretation exposes the exact picofarad calculation, so the compact marking never has to be trusted without a readable explanation.

Exact encoding and values that need another notation

The three-digit system has a limited vocabulary: two significant digits and a multiplier from zero through nine. This tool therefore returns a code only when the requested capacitance can be represented exactly by that structure. It does not quietly round a value with three or more meaningful digits to the nearest available marking, because that could cause you to order or fit a component with a different nominal capacitance. A value such as 4.7 nF is exact and becomes 472, while a value such as 4.75 nF cannot be expressed exactly in the standard three-digit form and produces a clear input error. Very small fractional-picofarad values and values beyond the available multiplier range are rejected for the same reason. This policy concerns the nominal printed value only. Real capacitors also have tolerance, voltage rating, dielectric, temperature behavior, and package constraints; those properties are not encoded by these three digits and must still be checked on the datasheet or reel label.

Using the result in design and inventory workflows

Use the calculator when moving between a schematic value and the short marking visible on a ceramic disc or multilayer capacitor. The main result is a three-character code suitable for copying into a bill of materials note, inspection checklist, storage-bin label, or purchasing search. Supporting fields give the capacitance in picofarads, a convenient normalized unit, the two significant digits, and the decimal multiplier. Together they make automated validation straightforward: a script can compare the code while a person reviews the normalized value. The browser version is useful at a bench because the conversion stays local and requires no account. For repeated catalog cleanup or manufacturing checks, the same deterministic calculation is available through the API for $0.002 per request. Identical input always produces identical output, and the calculation uses no network service, random choice, or clock. Remember that markings can be accompanied by letters identifying tolerance or other characteristics; enter only the capacitance value here, and treat those suffixes as separate component specifications.

What you can do with it

Prepare a bill of materials

Turn schematic capacitance values into the compact markings technicians expect to see during assembly and inspection.

Identify storage bins

Generate a checked three-digit label for drawers or bags while retaining a readable normalized capacitance alongside it.

Validate component data

Compare supplier or inventory markings against nominal capacitance values in an automated, deterministic workflow.

FAQ

What does the third digit mean?

It is the base-ten multiplier in picofarads: append that many zeros to the first two digits.

What code represents 100 nF?

The code is 104 because 10 x 10^4 pF equals 100,000 pF, or 100 nF.

Why was my capacitance rejected?

The value may be missing a unit, non-positive, outside the multiplier range, or not exactly expressible with two significant digits and one multiplier digit.

Does the code include tolerance or voltage rating?

No. The three digits encode nominal capacitance only; check any letters, package information, and datasheet specifications separately.

How much does the API conversion cost?

Each API request costs $0.002. The calculator can also run free in the browser.

For developers — API access

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

API endpoint

POSThttps://api.kit.forhosting.com/elec/capacitor-code-encode

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

Call it from your stack

curl -X POST https://api.kit.forhosting.com/elec/capacitor-code-encode \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"capacitance":"100 nF"}'

const res = await fetch("https://api.kit.forhosting.com/elec/capacitor-code-encode", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "capacitance": "100 nF"
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/elec/capacitor-code-encode",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "capacitance": "100 nF"
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/elec/capacitor-code-encode", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"capacitance":"100 nF"}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"capacitance":"100 nF"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/elec/capacitor-code-encode", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "capacitance": "100 nF"
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "elec.capacitor_code_encode",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Pricing

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

Errors

HTTP	Code	Meaning
`401`	`unauthorized`	Missing or invalid API key.
`402`	`insufficient_balance`	Your balance doesn't cover the task price.
`404`	`unknown_type`	That task type doesn't exist.
`429`	`rate_limited`	Too many requests. Use the webhook instead of polling.

Read the full KIT documentation →