Catalytic activity converter
One microkatal equals 60 enzyme units (U). Convert catalytic activity between katals, microkatals, nanokatals and enzyme units, with the step through katals shown so you can paste it into a lab notebook or a methods section. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 1
- From
- µkat
- To
- U
- Result
- 60 U
- Converted
- 60
- Value kat
- 0.000001
- Factor
- 60
A catalytic activity converter turns one enzyme-activity magnitude into another unit without spreadsheet factors or mental powers of ten. Enter a finite value plus a source unit and a target unit among katals, microkatals, nanokatals, and traditional enzyme units; the tool returns the converted activity, the SI intermediate in katals, the exact unit factor applied, and step-by-step substitution lines you can paste into a lab notebook or methods section. Biochemists comparing assay certificates, clinical chemistry labs converting U to µkat for SI reporting, students checking textbook enzyme kinetics examples, and instrument firmware mapping reagent-kit labels all need the same deterministic path.
Which catalytic activity units are supported and how conversion works
This capability converts among the four catalytic-activity labels that dominate enzyme assays, clinical chemistry, and biochemistry teaching. Katals (kat) are the SI coherent unit of catalytic activity—one mole of substrate converted per second—and the internal hub: every conversion multiplies the input by how many katals equal one source unit, then divides by how many katals equal one target unit.
Microkatals and nanokatals are the common SI submultiples used when pure katals would print tiny decimals: one microkatal is exactly one millionth of a katal, and one nanokatal is exactly one billionth of a katal. The traditional enzyme unit U is defined as one micromole of substrate converted per minute under specified assay conditions; in SI terms that is exactly one millionth of a mole divided by sixty seconds, so one U equals one microkatal divided by sixty, or one-point-six-six-six-times-ten-to-the-minus-eight katals.
Equivalently, one katal equals sixty million enzyme units, and one microkatal equals sixty enzyme units—relationships every clinical lab method sheet still quotes when moving between legacy U and SI µkat reporting. Micro accepts both the Greek mu and the Latin u spelling, so ukat and µkat both mean microkatal. Same-unit requests succeed and return the input magnitude with a short message that no change of unit was required.
Practical tips, limits, and when to use this landing
Round-trip checks are straightforward: convert A to B and B back to A and confirm you recover the original within the published twelve-decimal rounding. Classic teaching pairs include one katal equals sixty million enzyme units, one microkatal equals sixty enzyme units, one enzyme unit equals sixteen-point-six-six-seven nanokatals, and one thousand enzyme units equals about sixteen-point-six-six-seven microkatals. Stay inside the absolute range so intermediate katal values cannot overflow; for very large industrial biocatalyst inventories choose kat rather than expanding everything to nkat.
This landing targets people searching for a catalytic activity converter, katal to enzyme unit, U to µkat, microkatal converter, or nanokatal conversion online; it is not a general length-weight-temperature unit converter, not a specific-activity calculator that divides by protein mass, and not a Michaelis-Menten kinetics solver.
What you can do with it
Clinical chemistry SI reporting
Labs convert legacy enzyme results reported in U into µkat or nkat for SI-compliant method sheets and external quality-assessment submissions.
Assay kit label reconciliation
Biotech teams map vendor reagent activities labeled in enzyme units onto katal-based process models without hand-maintained spreadsheet factors.
Teaching and homework checks
Students verify textbook conversions among kat, µkat, nkat, and U, including the exact one-µkat-equals-sixty-U relationship, against deterministic steps.
FAQ
What is a katal?
Microkatal and nanokatal are SI submultiples (10⁻⁶ and 10⁻⁹ kat).
Does this convert specific activity (U/mg)?
No. It converts pure catalytic activity magnitudes only. Divide by protein mass yourself if you need specific activity.
Is the catalytic activity converter free?
The browser tool is free and runs locally.
How do I convert enzyme units (U) to µkat?
Divide the U value by 60, since one microkatal equals 60 enzyme units. For example, 1000 U is about 16.667 µkat. Choose U as the starting unit and µkat as the target to get it directly.
What is an enzyme unit (U)?
It is the amount of enzyme that converts one micromole of substrate per minute under set assay conditions. In SI terms one U equals about 16.667 nanokatals, because the katal counts moles per second instead.
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/catalytic-activity \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":1,"from":"U","to":"µkat"}'const res = await fetch("https://api.kit.forhosting.com/conv/catalytic-activity", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 1,
"from": "U",
"to": "µkat"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/catalytic-activity",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 1,
"from": "U",
"to": "µkat"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/catalytic-activity", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":1,"from":"U","to":"µkat"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":1,"from":"U","to":"µkat"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/catalytic-activity", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"value": 1,
"from": "U",
"to": "µkat"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.catalytic_activity",
"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.
Limits
max_abs | 1000000000000000000 |
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
Unknown unit names fail with a clear invalid_input error instead of silent wrong factors.
Which catalytic activity units are supported and how conversion works
Canonical symbols returned by the API are kat, µkat, nkat, and U. English names such as katal, microkatal, nanokatal, and enzyme unit resolve to those same symbols, as do common aliases like ukat, EU, and units. If the name is not on the supported list the solver rejects the request with invalid_input naming the bad field and listing example units, so clients never guess whether a typo produced a wrong number. Absolute magnitude must stay within the published one-quintillion limit so intermediate products remain finite in IEEE double precision on the Worker and in the browser.
How to call the API and read the response
Value must be a finite number or a strict numeric string within absolute limits of one quintillion. Wire this into laboratory information systems, clinical chemistry calculators, enzyme assay notebooks, or batch jobs that already hold an activity reading and only need a second unit for display, regulatory comparison, or kit transfer without shipping floating conversion tables in every app binary. Prefer bare numbers for value when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without thousand separators or unit suffixes stuck to the digits. Send a JSON body with three required fields: value (aliases activity, amount, and n), from (aliases from_unit, unit_from, and source), and to (aliases to_unit, unit_to, and target). From and to must resolve to supported unit names after alias normalization. On success the response echoes the rounded input value, canonical from and to labels, result and converted set to the same rounded target magnitude, value_kat as the SI intermediate in katals, unit as the target label, factor as the from-to multiplier, formula as the short equation string, message as an English summary, steps as ordered substitution lines, and supported_units as the full list of canonical identifiers. Failed validation—missing fields, non-finite numbers, values outside absolute limits, or an unknown unit name—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item and zero marginal unit price.
Practical tips, limits, and when to use this landing
Normalize display labels on your side if you need locale-specific spellings—this API always returns short canonical tokens such as kat, µkat, nkat, and U so automated tests stay stable. Prefer this capability when both endpoints are among the supported catalytic-activity units and you need deterministic factors and step strings; if you only need to reformat a number for a locale without changing physical unit, use a number-format capability instead. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when clients deliberately probe unknown unit names such as becquerel or gray that belong to other physical quantities.
Technical questions
How does an enzyme unit (U) relate to the katal?
By definition 1 U = 1 µmol/min. Exactly, 1 U = (10⁻⁶)/60 kat, so 1 kat = 6×10⁷ U and 1 µkat = 60 U.
What happens if I send an unknown unit name?
The API returns invalid_input naming the bad field and listing supported units (kat, µkat, nkat, U). Failed tasks are not charged.