Mole unit converter
1 mole is 1,000 millimoles, and one pound-mole is exactly 453.59237 moles. Convert an amount of substance between mol, mmol, µmol, kmol and lb-mol, and see the same quantity in all five units at once. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Amount-of-substance magnitude to convert
- 1
- Input amount-of-substance unit
- mol
- Output amount-of-substance unit
- mmol
- Result
- 1,000
- Moles
- 1
- Millimoles
- 1,000
- Micromoles
- 1,000,000
Amount of substance is the SI base quantity measured in moles, yet lab notebooks, process sheets, and engineering handbooks constantly switch among millimoles, micromoles, kilomoles, and pound-moles without restating the factors. People search for a mole unit converter when they need a reliable translation between those labels—not a molar-mass calculator, not a particle counter via Avogadro, and not a general multi-category unit toolbox. This capability accepts one finite amount plus from and to unit labels among moles, millimoles, micromoles, kilomoles, and pound-moles, bridges every conversion through the mole so results stay consistent, and returns the target value together with the same quantity expressed in all five units. Unrecognized unit names are rejected with a clear validation error instead of silently guessing a nearby symbol.
How the mole unit converter maps SI prefixes and the pound-mole
Start from the mole as the SI base unit of amount of substance and express every other unit as an exact fixed factor into moles. One millimole is one thousandth of a mole and one micromole is one millionth of a mole, so the milli and micro steps are pure powers of ten that lab glassware and assay reports use every day. One kilomole is one thousand moles, the scale preferred in large industrial mass balances and process-engineering textbooks.
The pound-mole, common in United States chemical engineering practice, is defined so that the numerical molecular weight equals the mass of one pound-mole in pounds; because the international avoirdupois pound is exactly zero point four five three five nine two three seven kilograms, one pound-mole equals exactly four hundred fifty-three point five nine two three seven gram-moles. This calculator never mixes those paths ad hoc.
It multiplies the input amount by the factor of the source unit to reach moles, then divides by the factor of the target unit to produce the result. Because every path shares the same intermediate mole, converting one mole to millimoles and then back, or comparing pound-moles to kilomoles, stays numerically consistent within ordinary floating-point precision. The tool does not multiply by Avogadro number to count particles, does not convert mass using molar mass, does not solve ideal-gas n from PV equals nRT, and does not fetch live chemical data.
It answers only the algebraic amount-of-substance unit conversion people mean when they type mole unit converter into a search bar and expect mol, mmol, µmol, kmol, and lb-mol.
What you enter and what you get back
Send three fields: amount, a finite number for the magnitude; from, a string naming the input unit; and to, a string naming the output unit. Both unit fields accept short keys and everyday words in any common casing, including mole or moles or mol, millimole or mmol, micromole or umol or µmol, kilomole or kmol, and pound-mole or lb-mol or lbmol. When a unit string is unknown the error message includes Unrecognized unit and lists the five supported families so clients can fix the label rather than guessing.
Classic checks include one mole becoming one thousand millimoles, one millimole becoming one thousand micromoles, one kilomole becoming one thousand moles, and one pound-mole becoming four hundred fifty-three point five nine two three seven moles.
Where dedicated mole conversion shows up in real work
Secondary-school and university chemistry courses constantly assign problems that give an amount in one unit and ask for another, often mixing millimoles from titration burettes with moles in the stoichiometric equation on the same worksheet. Analytical and clinical labs report micromolar and millimolar concentrations whose underlying amount fields still need consistent mol-based storage before reporting. Process engineers in plants that follow United States customary units balance reactors in pound-moles while equipment datasheets and SI suppliers speak in kilomoles, so a single conversion pass keeps storage metric while the UI localizes.
If you later need molar mass to mass conversion, Avogadro particle counts, mole fraction, molality, or ideal-gas amount from pressure and volume, treat those as separate search intents and landings rather than overloading this mole unit converter page.
What you can do with it
Lab notebook and titration prep
Convert moles, millimoles, and micromoles so titration volumes, stock dilutions, and answer keys share one ground truth.
Process engineering SI vs pound-moles
Normalize reactor and stream balances between kmol and lb-mol when plants mix SI suppliers with US customary practice.
LIMS and curriculum auto-graders
Accept mixed mol, mmol, and µmol tags from student work or instruments and store a single mole-based value for grading and audit.
FAQ
Which amount-of-substance units does this converter support?
Moles (mol), millimoles (mmol), micromoles (umol / µmol), kilomoles (kmol), and pound-moles (lbmol / lb-mol).
What happens if I send an unrecognized unit?
The error message includes Unrecognized unit and lists the supported families so you can correct the label.
How is the pound-mole defined here?
One pound-mole equals exactly 453.59237 moles (gram-moles), from the international avoirdupois pound definition. That is the same mass ratio used by SI-consistent chemical engineering tables.
Does it convert mass or count molecules?
No. It only converts amount-of-substance units. Molar mass to mass, Avogadro particle counts, and gas-law n from PV=nRT are different tools and search intents.
What does it cost?
The browser tool is free and runs locally.
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
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/amount-of-substance \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"amount":1,"from":"mol","to":"mmol"}'const res = await fetch("https://api.kit.forhosting.com/conv/amount-of-substance", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"amount": 1,
"from": "mol",
"to": "mmol"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/amount-of-substance",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"amount": 1,
"from": "mol",
"to": "mmol"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/amount-of-substance", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"amount":1,"from":"mol","to":"mmol"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"amount":1,"from":"mol","to":"mmol"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/amount-of-substance", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"amount": 1,
"from": "mol",
"to": "mmol"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.amount_of_substance",
"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
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
What you send and what you get back from the API and browser form
Missing fields, non-numeric amount strings, NaN, Infinity, and unrecognized unit labels fail with invalid_input and are not charged. On success the response echoes the cleaned amount, normalized from and to keys, the primary result in the target unit, the same quantity as moles, millimoles, micromoles, kilomoles, and pound_moles with twelve significant digits of stable precision, the mole factors used, the formula string, and method mole_bridge. Pricing for successful API calls is the published base of $0.002 per item; validation failures do not consume prepaid balance.
Where dedicated mole conversion shows up in real work
Data pipelines that ingest mixed LIMS or ERP payloads with mol, mmol, and lb-mol tags can call this capability once per reading instead of reimplementing the factors in every service. Because this capability is a pure parse engine, API pricing is the published base of $0.002 per successful item and failed validation does not consume balance.