Earthquake magnitude energy converter
A magnitude 6 earthquake radiates about as much energy as 15 thousand tons of TNT. Convert moment magnitude to joules, ergs or tons, kilotons and megatons of TNT, and back again, with the same Gutenberg–Richter relation every time. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 6
- From
- Mw
- To
- Ton tnt
- Result
- 15,080.2424588957
- From label
- moment magnitude
- To label
- ton of TNT
- Joules
- 63,095,734,448,019.43
An earthquake magnitude energy converter turns a seismic size written as moment magnitude into radiated energy in joules or TNT equivalent—and the reverse—without hunting Gutenberg–Richter tables or building spreadsheet logarithms by hand.
Supported units and how magnitude energy is computed
When the source is Mw, radiated energy in joules is obtained from the Gutenberg–Richter energy–magnitude relation E equals ten raised to the power of one point five times magnitude plus four point eight. When the source is already an energy or TNT unit, the value is multiplied by a fixed joules-per-unit factor.
The target is then produced either by dividing joules by the target energy factor or, when the target is Mw, by inverting the same logarithm: magnitude equals log base ten of energy in joules minus four point eight, all divided by one point five. One ton of TNT is defined as exactly four point one eight four times ten to the nine joules, so kiloton and megaton scales are exact thousand and million multiples of that factor.
Because energy units share a single joule intermediate and magnitude always uses the same coefficients, converting A to B and B to A is consistent up to published rounding, and there is no pairwise matrix that can drift out of sync across releases.
Where earthquake energy figures get used
Use the free in-browser earthquake energy converter when you need a quick Mw-to-joules, joules-to-tons-of-TNT, or kiloton-to-magnitude check while reading a USGS summary, a textbook problem, a documentary script, or a risk briefing. Open the page, enter the number and units, and copy the result without installing a seismology package, a spreadsheet log table, or a desktop calculator pack. Source inputs follow the same retention rules as other KIT parse items, and results are safe to cache because the algorithm is fully deterministic.
What you can do with it
Science journalism and explainers
Translate a reported Mw into joules and tons of TNT so headlines and infographics can compare earthquake energy to familiar blast scales without hand-written log tables.
Risk briefings and museum exhibits
Normalize kilotons, megatons, joules, and Mw for dashboards and interactive exhibits that need the same Gutenberg–Richter factors every time.
FAQ
What formula links magnitude and energy?
The Gutenberg–Richter educational relation log10(E)=1.5×Mw+4.8 with E in joules. Inverse: Mw=(log10(E)−4.8)/1.5.
What happens if I send an unknown unit?
The message names the field and lists supported units. Validation failures are not charged.
Is the earthquake magnitude energy converter free?
The browser tool runs free on your device.
Can I turn kilotons or joules back into a magnitude?
Yes. The converter inverts the same relation: it takes the base-ten logarithm of the energy in joules, subtracts 4.8 and divides by 1.5, so both directions always agree.
Is a ton of TNT an exact unit?
Yes. One ton of TNT is defined as exactly 4.184 billion joules, so kilotons and megatons are exact thousand and million multiples of that figure, with no rounding hidden in between.
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/earthquake-energy \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":6,"from":"Mw","to":"ton_tnt"}'const res = await fetch("https://api.kit.forhosting.com/conv/earthquake-energy", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 6,
"from": "Mw",
"to": "ton_tnt"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/earthquake-energy",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 6,
"from": "Mw",
"to": "ton_tnt"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/earthquake-energy", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":6,"from":"Mw","to":"ton_tnt"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":6,"from":"Mw","to":"ton_tnt"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/earthquake-energy", 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": 6,
"from": "Mw",
"to": "ton_tnt"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.earthquake_energy",
"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
The browser tool runs free on your device; the prepaid API charges $0.002 per successful item when classrooms, newsrooms, and risk pipelines need the same contract from servers and automation.
Supported units and how magnitude energy is computed
The converter accepts moment magnitude under the canonical code Mw together with linear energy families: J for joule, kJ for kilojoule, MJ for megajoule, GJ for gigajoule, TJ for terajoule, erg for the CGS energy unit, ton_tnt for tons of TNT equivalent, kt_tnt for kilotons of TNT, and Mt_tnt for megatons of TNT. Friendly aliases such as magnitude, moment magnitude, joule, joules, kiloton, megaton, ton of TNT, and tnt are normalized case-insensitively so forms and APIs can pass either short codes or full names.
Request shape, response fields, and unknown-unit errors
The error message names the bad field and lists the supported set so clients can correct forms without guessing. Send a JSON body with three required fields: value as a finite number, from as the source unit string, and to as the target unit string. Aliases amount, quantity, and magnitude are accepted for value; unit_from and source for from; unit_to and target for to. On success the response echoes the canonical from and to codes, human-readable from_label and to_label strings, the converted result, the intermediate joules quantity, the same energy expressed as tons_tnt, the equivalent magnitude_mw when energy is positive, a short formula line suitable for UI display, the method tag gutenberg_richter_energy, a relation string documenting the fixed coefficients and TNT definition, and the fixed list of units_supported. Missing value, non-finite numbers such as NaN or Infinity, missing unit fields, negative energy amounts, non-positive energy when converting to magnitude, magnitudes that overflow double-precision energy, and any token that does not map to a supported unit fail with invalid_input and are not charged after the engine rejects the request. Zero energy converts cleanly among linear energy units but cannot produce a finite magnitude, so magnitude_mw is omitted in that edge case. Identical inputs always yield identical JSON because the path is pure arithmetic with no randomness, no remote lookup, and no dependence on the wall clock, which makes the endpoint safe to pin in continuous-integration goldens and SDK contract tests across classrooms and production newsroom tools.
Browser use, API pricing, and everyday seismic workflows
Switch to the prepaid API when a classroom platform, science journalism CMS, emergency-management dashboard, museum exhibit backend, or homework checker must convert earthquake energy at scale under a stable KIT contract at $0.002 per successful item; validation failures that raise invalid_input do not consume balance after rejection. Pair this endpoint with general energy converters when a product pipeline also needs everyday joules-to-kilowatt-hours work, or call it alone when search traffic is specifically for earthquake magnitude energy—moment magnitude, joules, tons of TNT, kilotons, and megatons—rather than a generic unit switchboard. Authors shipping mobile apps or chatbots can map the result, joules, tons_tnt, magnitude_mw, and formula fields directly into cards that show both the number and the conversion path students, journalists, and planners expect on paper.
Integration use cases
Classroom and homework checkers
Convert magnitude to energy and back in lab exercises with a prepaid, deterministic API contract and clear invalid_input on unknown units or non-positive energy.
Technical questions
Which units does the earthquake energy converter support?
Moment magnitude (Mw), joules and SI multiples (J, kJ, MJ, GJ, TJ), erg, and TNT equivalents (ton_tnt, kt_tnt, Mt_tnt). Full names and common aliases are accepted; unknown units raise invalid_input.
How do I convert magnitude 6 to tons of TNT?
Send JSON with value: 6, from: "Mw", to: "ton_tnt". The response includes result, joules, tons_tnt, magnitude_mw, and a readable formula line.