Physical action converter
1 joule-second is 10,000,000 erg-seconds. This converter moves physical action between J·s, eV·s, erg·s, N·m·s and the Planck constants h and ħ, and shows each substitution step for your report or lab notebook. 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
- J·s
- To
- erg·s
- Result
- 10,000,000 erg·s
- Converted
- 10,000,000
- Value js
- 1
- Factor
- 10,000,000
A physical action converter turns one action magnitude—energy times time—into another unit without spreadsheet formulas or scattered factor tables. Enter a finite value plus a source unit and a target unit among joule-seconds, electronvolt-seconds, erg-seconds, the Planck constant h as a unit of action, the reduced Planck constant ħ, and newton-metre-seconds; the tool returns the converted action, the SI intermediate in J·s, the exact unit factor applied, and step-by-step substitution lines you can paste into a report or lab notebook. Quantum mechanics students comparing ħ scales, spectroscopists working in eV·s, cgs handbooks listing erg·s, and engineers checking SI action integrals all need the same deterministic path.
Which physical action units are supported and how conversion works
This capability converts among six everyday physical-action units that dominate SI textbooks, quantum mechanics courses, cgs handbooks, and laboratory notes. Joule-seconds (J·s) are the SI coherent unit of action—energy times time, with dimensions mass times length squared over time—and they are the internal hub: every conversion multiplies the input by how many joule-seconds equal one source unit, then divides by how many joule-seconds equal one target unit. Newton-metre-seconds (N·m·s) are an exact identity with J·s because one newton-metre is exactly one joule.
Erg-seconds use the exact cgs link one erg equals ten to the minus seven joules, so one erg-second equals ten to the minus seven joule-seconds. The Planck constant h is fixed at six point six two six zero seven zero one five times ten to the minus thirty-four joule-seconds (exact SI 2019 defining constant) and may be used as a unit of action itself. 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
Prefer sending bare numbers for value when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without currency symbols or thousand separators. 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 for macroscopic units; Planck-scale h and ħ values use scientific magnitude, so compare relative error carefully near double precision.
When teaching unit analysis, pair classic examples such as one joule-second to ten million erg-seconds, one electronvolt-second expressed in joule-seconds using the exact elementary charge, and one ħ expressed in J·s using h over two pi. Stay inside the absolute range so intermediate J·s values cannot overflow when scaling between quantum units and SI.
This landing targets people searching for a physical action converter, joule second to eV s, erg second to J s, or planck constant unit conversion online; it is not a general energy-only converter, not a torque calculator, and not an angular-momentum solver for arbitrary symbols outside the supported table.
What you can do with it
SI ↔ cgs action tables
Older mechanics and continuum notes list action integrals in erg·s while modern SI papers use J·s; convert once with the exact 10⁻⁷ factor and keep both columns aligned.
Quantum ħ and h scales
Students and researchers express phase-space or uncertainty-related action in units of h or ħ and need a deterministic SI J·s (or eV·s) value for code and reports.
Homework and unit-analysis checks
Learners convert action homework values between J·s, eV·s, and erg·s and compare deterministic steps against hand calculations before submission.
FAQ
Is N·m·s the same as J·s?
Yes for action dimensions: 1 N·m equals exactly 1 J, so 1 N·m·s equals 1 J·s. This converter treats them as an exact identity through the SI hub.
Is the physical action converter free?
The browser tool is free and runs locally.
How many erg-seconds are in one joule-second?
Exactly 10,000,000. One erg is 10⁻⁷ joules, so one erg-second is 10⁻⁷ joule-seconds, and going the other way multiplies by ten million.
What is the Planck constant in joule-seconds?
It is exactly 6.62607015 × 10⁻³⁴ J·s, a value fixed by the SI redefinition of 2019. The converter also lets you use h itself as a unit of action.
How is ħ related to h?
The reduced Planck constant ħ is h divided by two pi. Quantum mechanics courses use ħ constantly, so converting a value into ħ units shows how many of those natural steps it contains.
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/action-physics \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":1,"from":"J·s","to":"eV·s"}'const res = await fetch("https://api.kit.forhosting.com/conv/action-physics", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 1,
"from": "J·s",
"to": "eV·s"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/action-physics",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 1,
"from": "J·s",
"to": "eV·s"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/action-physics", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":1,"from":"J·s","to":"eV·s"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":1,"from":"J·s","to":"eV·s"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/action-physics", 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": "J·s",
"to": "eV·s"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.action_physics",
"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 | 1000000000000 |
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 physical action units are supported and how conversion works
Electronvolt-seconds use the exact SI 2019 elementary charge: one electronvolt equals one point six zero two one seven six six three four times ten to the minus nineteen joules, frozen here so JSON never drifts with a network lookup. The reduced Planck constant ħ equals h divided by two pi, computed deterministically with the platform Math.PI so browser and Worker agree bit-for-bit after rounding. Common aliases are accepted case-insensitively: Js and joule second for J·s; eV s and electronvolt-second for eV·s; erg s for erg·s; planck constant for h; hbar, h-bar, and reduced planck for ħ; N m s and kg m2/s for N·m·s. If the name is not on that list the solver rejects the request with invalid_input naming the bad field and listing supported units, so clients never guess whether a typo produced a wrong number. Negative actions are allowed for signed conventions in path integrals or oriented phase-space quantities; absolute magnitude must stay within the published one-trillion 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 trillion. Wire this into dashboards, quantum lab notebooks, homework checkers, or batch jobs that already hold an action reading and only need a second unit for display, paper comparison, or regulatory reporting without shipping floating conversion tables in every app binary. Send a JSON body with three required fields: value (aliases action, amount, n, and s), 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_js as the SI intermediate in joule-seconds, 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 six 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 the short canonical tokens J·s, eV·s, erg·s, h, ħ, and N·m·s so automated tests stay stable. Prefer this capability when both endpoints are among the six supported action units and you need deterministic factors and step strings; if you only need energy between joules and electronvolts without the time factor, use an energy converter instead. Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when clients deliberately probe unknown unit names.
Technical questions
Which physical action units can I convert?
Joule-seconds (J·s), electronvolt-seconds (eV·s), erg-seconds (erg·s), Planck constant units h, reduced Planck ħ (hbar), and newton-metre-seconds (N·m·s), including common aliases such as Js, eV s, hbar, and planck constant.
What happens if I send an unknown unit name?
The API returns invalid_input, names the bad field, and lists the supported units. The failed task is not charged.
Are results deterministic across browser and API?
Yes. Handler and widget share the same lib.js solve path with fixed conversion factors (exact SI 2019 e and h, ħ = h/(2π)) and twelve-decimal rounding, so golden examples match production.