ForHosting KIT · Unit converters

Chinese chi/cun length converter

One chi is a third of a metre: 33.333333 cm with six decimals. Enter a length in chi and see it in metres, centimetres, millimetres and inches, plus the matching cun, fen and zhang of the Chinese decimal chain. Free in your browser.

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Run — free How it works & API

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Worked example

If you enter

Chi: 1
Decimal places: 6

You get

M: 0.333333
Cm: 33.333333
Mm: 333.333333
Cun: 10

Search intent: chi to cm / cun Chinese. No network calls, no random seeds, and no server state are required for a correct answer. Failed

A decimal chain anchored to the metre

The traditional Chinese lengths form a simple decimal ladder: ten fen make a cun, ten cun make a chi and ten chi make a zhang. The converter uses the metric chi, fixed at exactly one third of a metre, so every step of the ladder has a clear value in modern units. One chi is 33.333333 centimetres when shown with six decimals, a zhang is ten times that and a cun a tenth of it. Because the chain is decimal, moving between fen, cun, chi and zhang only means shifting the decimal point; the third comes in when you go to metres.

How the result is worked out and what to watch for

You enter a length in chi, and the converter divides it by three to get metres, then expresses the same length in centimetres, millimetres and inches, along with the matching cun, fen and zhang. A third has no exact decimal form, so the figures are rounded only once, at the end, to the decimals you choose, with halves going up. The usual slip is rounding the third too early and multiplying afterwards, which drifts on long measurements. Another is mixing up chi and cun: a cun is ten times shorter, so a figure in cun must be divided by ten before you enter it as chi.

FAQ

Locales?

EN-only delivery; Nitro hydrates the other seven languages.

How many inches is one chi?

About 13.12336 inches. The converter shows that figure next to the metric length, so a chi taken from a Chinese document can be compared directly with a measurement in inches.

How are fen, cun, chi and zhang related?

They form a decimal chain: ten fen make a cun, ten cun make a chi and ten chi make a zhang. So one chi is 10 cun, 100 fen or 0.1 zhang, and the result lists all of them.

Why is a chi 33.333333 cm and not a round number?

Because the metric chi is one third of a metre, and a third never ends in decimals. The converter rounds only once, at the end, to the decimals you choose, with halves rounded up.

How do I convert cun to centimetres?

Enter the length as chi, keeping in mind that a cun is a tenth of a chi, so one cun is 0.1 chi. The result is about three and a third centimetres, and the cun line confirms the count.

Related tools

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/conv/chi-cun-length

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/conv/chi-cun-length \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"m":0.333333}'

const res = await fetch("https://api.kit.forhosting.com/conv/chi-cun-length", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${process.env.KIT_KEY}`,
    "Content-Type": "application/json"
  },
  body: JSON.stringify({
    "m": 0.333333
  })
});
const { task_id } = await res.json();

import os, requests

res = requests.post(
    "https://api.kit.forhosting.com/conv/chi-cun-length",
    headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
    json={
    "m": 0.333333
},
)
task_id = res.json()["task_id"]

<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/chi-cun-length", false, stream_context_create([
  "http" => [
    "method"  => "POST",
    "header"  => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
    "content" => '{"m":0.333333}',
  ],
]));
$task = json_decode($res, true);

body := bytes.NewBufferString(`{"m":0.333333}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/chi-cun-length", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)

Example request

{
  "m": 0.333333
}

Example response

{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "conv.chi_cun_length",
  "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.

Technical notes

Convert Chinese fen/cun/chi/zhang body-length chain to SI using metric chi = 1/3 m. The calculator is free in the browser, deterministic, and identical in the API path. Inputs are validated before any arithmetic so invalid payloads fail with invalid_input. Half-up rounding is applied once from raw IEEE results when decimals are requested. Use the same JSON contract from spreadsheets, CMS hooks, automation, or teaching demos.

How it works

No network calls, no random seeds, and no server state are required for a correct answer. Failed jobs are not billed. Landings target the stated search intent with precise keywords. Prefer explicit units and ranges over silent coercion of bad types. When a field is optional, defaults are documented in params and echoed in the Convert Chinese fen/cun/chi/zhang body-length chain to SI using metric chi = 1/3 m. 1 zhang = 10 chi; 1 chi = 10 cun = 1/3 m; 1 cun = 10 fen. The calculator is free in the browser, deterministic, and identical in the API path. Inputs are validated before any arithmetic so invalid payloads fail with invalid_input. Half-up rounding is applied once from raw IEEE results when decimals are requested. Use the same JSON contract from spreadsheets, CMS hooks, automation, or teaching demos.

Inputs, limits and rounding

Outputs echo inputs for logging. No network calls, no random seeds, and no server state are required for a correct answer. Failed jobs are not billed. Landings target the stated search intent with precise keywords. Prefer explicit units and ranges over silent coercion of bad types. When a field is optional, defaults are documented in params and echoed in the output. Provide required JSON fields. Optional decimals use half-up once from raw IEEE values. Invalid types or ranges raise invalid_input. The calculator is free in the browser, deterministic, and identical in the API path. Inputs are validated before any arithmetic so invalid payloads fail with invalid_input. Half-up rounding is applied once from raw IEEE results when decimals are requested. Use the same JSON contract from spreadsheets, CMS hooks, automation, or teaching demos.

When to use it

Use when the search intent matches this tool. No network calls, no random seeds, and no server state are required for a correct answer. Failed jobs are not billed. Landings target the stated search intent with precise keywords. Prefer explicit units and ranges over silent coercion of bad types. When a field is optional, defaults are documented in params and echoed in the output. Convert Chinese fen/cun/chi/zhang body-length chain to SI using metric chi = 1/3 m. The calculator is free in the browser, deterministic, and identical in the API path. Inputs are validated before any arithmetic so invalid payloads fail with invalid_input. Half-up rounding is applied once from raw IEEE results when decimals are requested. Use the same JSON contract from spreadsheets, CMS hooks, automation, or teaching demos.

Integration use cases

Quick check

Use the free widget to verify a formula before production.

Automation

Call the API with the same JSON contract from scripts or CMS.

Teaching

Show pinned golden examples without proprietary software.

Technical questions

Is the browser widget free?

Yes. Tier A is free client-side with the same core as the API.

Does it use the network?

No. Computation is local and deterministic.

What on bad input?

invalid_input is thrown; failed jobs are not billed.

API compatible?

Yes — same JSON fields as params.json.

Read the full KIT documentation →

Run — free