Electronvolts to joules converter
One electronvolt is exactly 1.602176634 × 10⁻¹⁹ joules. Enter an energy in eV and get joules with that fixed factor instead of a rounded shortcut, so atomic, solid-state and particle physics results match modern SI references. Free in your browser.
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- Your data stays on your device
Run — free
Worked example
- Electronvolts
- 1
- Result
- 0 J
- Converted
- 0
- Joules
- 0
- From unit
- eV
An electronvolts to joules converter turns a particle or atomic energy reading into the SI joule value used in physics labs, solid-state notes, and scientific reporting. Approximate mental shortcuts such as one point six times ten to the minus nineteen are rejected in favour of the fixed elementary-charge constant, so homework checks and lab exports match modern CODATA and SI references.
Why electronvolts and joules meet at 1.602176634×10⁻¹⁹
The electronvolt remains the everyday scale for atomic, molecular, solid-state, nuclear, and particle-physics energies because a single electron accelerated through one volt gains a convenient amount of kinetic energy, far smaller than a joule yet exact by definition.
Since the 2019 SI redefinition, the elementary charge is fixed at exactly one point six zero two one seven six six three four times ten to the minus nineteen coulombs, so one electronvolt equals that charge times one volt and is therefore exactly one point six zero two one seven six six three four times ten to the minus nineteen joules. That makes the conversion a single exact multiplication: joules equals electronvolts times that constant. No older CODATA rounded table or approximate textbook shortcut is used—the factor is pure SI.
Teachers can contrast the exact path with a rough one point six times ten to the minus nineteen rule of thumb so students see how truncating the factor accumulates when they scale from milli-electronvolts to mega-electronvolts or when they convert large ensembles of particles into total energy budgets.
Practical tips, checks, and related searches
Round-trip sanity checks are easy: convert one electronvolt and confirm you receive exactly one point six zero two one seven six six three four times ten to the minus nineteen joules after rounding, or convert thirteen point six electronvolts—the hydrogen ground-state ionization energy scale often used in textbooks—and confirm the product matches the same exact factor times thirteen point six. If your source table quotes kilo-electronvolts or mega-electronvolts, multiply by one thousand or one million to obtain electronvolts before calling this tool, then read joules from the response.
Stay inside the absolute range so the input cannot exceed the published finite limits the solver must reject. When teaching unit analysis, pair an atomic binding-energy example with a macroscopic joule budget so students see why particle energies look tiny in SI yet remain exact under the fixed elementary charge.
This landing targets people searching for electronvolts to joules, convert eV to J, or an exact 1.602176634e-19 calculator; it is not a multi-unit energy hub, not a joules-to-electronvolts primary form, not a photon wavelength or frequency converter, and not a radiation dose tool. Prefer this capability when the input is already in electronvolts and you only need joules; if you must convert among many energy units in one call, use a broader energy unit converter instead.
Always keep power and energy labels separate: electronvolts measure energy, not power, so runtime or rate quantities belong elsewhere.
What you can do with it
Atomic and solid-state energy tables
Convert textbook or lab electronvolt readings into SI joules for modern reports, band-gap notes, and spreadsheet energy balances with the same exact SI factor every row.
FAQ
How many joules are in one electronvolt?
Exactly 1.602176634×10⁻¹⁹ joules: joules = electronvolts × 1.602176634e-19. This is the exact SI 2019 definition from the fixed elementary charge.
Is 1.6×10⁻¹⁹ J close enough?
That is a common classroom approximation. This tool uses the exact fixed factor 1.602176634×10⁻¹⁹ J so results match modern SI tables, not a rounded mental shortcut.
Does this convert joules back to electronvolts?
No. This tool is one-way electronvolts to joules. To invert, divide joules by 1.602176634e-19 on your side or use a dedicated inverse converter if available.
Is the electronvolts to joules converter free?
The browser tool is free and runs locally.
How do I convert keV or MeV to joules?
Turn the value into electronvolts first: multiply kilo-electronvolts by 1000 or mega-electronvolts by a million. Then enter that figure and read the joules, which keeps the exact factor intact.
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/electronvolts-to-joules \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"electronvolts":1}'const res = await fetch("https://api.kit.forhosting.com/conv/electronvolts-to-joules", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"electronvolts": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/electronvolts-to-joules",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"electronvolts": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/electronvolts-to-joules", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"electronvolts":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"electronvolts":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/electronvolts-to-joules", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"electronvolts": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.electronvolts_to_joules",
"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
Invalid or missing input fails with a clear invalid_input error instead of inventing a number.
Why electronvolts and joules meet at 1.602176634×10⁻¹⁹
The joule is the SI coherent unit of energy: one newton-metre, one watt-second, and the common reporting unit for heat and work in modern science and engineering.
How to call the API and what comes back
Absolute values must stay within the published limit of one trillion. Prefer bare numbers when you control the client; string numbers are accepted only when they match a strict finite numeric pattern without unit suffixes or thousand separators. Send a JSON body with one required finite number field named electronvolts. Aliases ev, eV, electron_volts, value, energy, and ev_value are accepted so SDK clients and form posts can use the name that fits the product. On success the response echoes rounded electronvolts, sets joules, result, and converted to the same rounded joule magnitude, unit to the token J, from_unit to eV and to_unit to J, factor and joules_per_ev to one point six zero two one seven six six three four times ten to the minus nineteen, formula to the string joules equals electronvolts times 1.602176634e-19, message to a short English summary, and steps to an ordered array of substitution lines. Failed validation—missing fields, non-finite numbers, bare plus or minus signs, non-numeric strings, values outside absolute limits, or a non-finite converted result—returns invalid_input and is never charged. Pricing is a flat $0.002 per successful request with unit item. Do not send kiloelectronvolts or megaelectronvolts as if they were plain electronvolts: scale to eV first, or multiply the result by the appropriate power of ten after conversion when you keep the input in keV or MeV on your side.
Practical tips, checks, and related searches
Failed tasks that return invalid_input do not consume prepaid balance, which keeps exploratory scripts cheap when learners deliberately omit electronvolts or pass text.
Integration use cases
Homework and exam unit checks
Students convert classroom eV values to joules and compare hand work against deterministic steps before submitting worksheets or coding kata fixtures.
Particle and nuclear energy alignment
Spectra and reaction notes that quote electronvolts can be normalized to joules for SI datasheets, control logic, and API payloads without fragile hand-typed factor tables.
Technical questions
What happens on invalid input?
Missing fields, non-finite values, non-numeric strings, or values outside the absolute limits return invalid_input and are never charged.