Fracture toughness converter
Put fracture toughness from any datasheet into the unit you need: 50 MPa·√m is about 45.502 ksi·√in, using the exact inch and the exact pascal-per-ksi factor, across seven units. Handy for alloy comparisons, fracture reports and allowables memos. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 50
- From
- MPa_m05
- To
- ksi_in05
- Result
- 45.5023852515
- From label
- megapascal root meter
- To label
- ksi root inch
- Si
- 50,000,000
A fracture toughness converter turns a stress-intensity quantity written in one unit into another without hunting handbook tables or rewriting spreadsheet formulas by hand.
Supported units and how the conversion is computed
Factors follow SI identity and exact length and pressure definitions: one megapascal root meter is exactly one million pascal root meters; one ksi root inch uses the international definition of the inch as zero point zero two five four metres together with the conventional pascal-per-ksi factor; one N per millimetre to the three-halves expands through the exact millimetre-to-metre power.
Because the intermediate is always SI, converting A to B and B to A is consistent up to the published rounding of twelve decimal places, and there is no pairwise matrix that can drift out of sync. Energy release rate, J-integral, crack-tip opening displacement, and geometry-based K formulas are intentionally out of scope so materials, fracture-mechanics, and QA users get predictable unit-only results under one clear convention.
For datasheets, fracture reports and memos
Use the free in-browser fracture toughness converter when you need a quick megapascal-root-meter to ksi-root-inch check, a pascal-root-meter to N-per-millimetre normalization, or a psi-root-inch to MPa√m switch while reading a materials datasheet, ASTM fracture report, aerospace allowables memo, or homework problem. Open the page, enter the number and units, and copy the result without installing a spreadsheet, a unit library, 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.
Authors shipping mobile apps or chatbots can map the result and formula fields directly into cards that show both the number and the conversion path engineers, students, and technicians expect on paper.
What you can do with it
Materials datasheet and KIc table harmonization
Normalize vendor KIc values from MPa·√m to ksi·√in (or the reverse) so alloy comparison tables share one unit column before ranking or plotting.
FEA and fracture-mechanics pipelines
Pre-processors convert mixed SI and US customary toughness inputs to a single canonical unit before mesh runs or crack-growth models consume them.
FAQ
How do I convert 50 MPa·√m to ksi·√in?
The response includes result (about 45.502 ksi·√in), an si intermediate in Pa·√m, and a readable formula.
What is the exact factor between ksi·√in and MPa·√m?
One ksi root inch equals 6.894757293168361 × √0.0254 megapascal root meters (about 1.098843 MPa·√m), using the exact inch definition and the conventional ksi-to-pascal factor. The converter applies that chain through the Pa·√m intermediate.
What happens if I send an unknown unit?
The message names the field and lists supported units. Validation failures are not charged.
Is the fracture toughness converter free?
The browser tool runs free on your device.
Can it calculate K from crack size or the J-integral?
No. It only converts a toughness value you already have between units. Energy release rate, J-integral, crack-tip opening displacement and geometry-based K formulas are left out on purpose, so results stay a pure unit change.
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/fracture-toughness \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":50,"from":"MPa_m05","to":"ksi_in05"}'const res = await fetch("https://api.kit.forhosting.com/conv/fracture-toughness", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 50,
"from": "MPa_m05",
"to": "ksi_in05"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/fracture-toughness",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 50,
"from": "MPa_m05",
"to": "ksi_in05"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/fracture-toughness", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":50,"from":"MPa_m05","to":"ksi_in05"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":50,"from":"MPa_m05","to":"ksi_in05"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/fracture-toughness", 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": 50,
"from": "MPa_m05",
"to": "ksi_in05"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.fracture_toughness",
"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 pipelines need the same contract from servers and automation.
Supported units and how the conversion is computed
The converter accepts seven fracture-toughness families under stable canonical codes: Pa_m05 for the coherent SI pascal root meter, kPa_m05 for kilopascal root meter, MPa_m05 for the engineering megapascal root meter most common in KIc tables, GPa_m05 for gigapascal root meter, ksi_in05 for ksi root inch used in US customary materials data, psi_in05 for psi root inch, and N_mm15 for newton per millimetre to the three-halves found in some European and standards sheets. Friendly aliases such as megapascal root meter, ksi root inch, pascal root meter, MPa√m, ksi√in, Pa√m, N/mm^{3/2}, and common symbol spellings are normalized so forms and APIs can pass either short codes or full names. Every request multiplies the input value by the exact pascal-root-meter factor for the source, then divides by the factor for the target.
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. Negative values are allowed when you need signed intermediate bookkeeping in a pipeline; zero converts cleanly to zero in every target unit. 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 and quantity 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 si quantity in pascal root meters with si_unit set to Pa_m05, the dimensionless factor from source to target, a short formula line suitable for UI display, the method tag fracture_toughness_si, and the fixed list of units_supported. Missing value, non-finite numbers such as NaN or Infinity, missing unit fields, 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. 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. Imperial-scale and SI-scale results share the same code path, so extreme magnitude pairs remain well-defined as long as IEEE double precision can represent the intermediate SI product.
Browser use, API pricing, and everyday workflows
Switch to the prepaid API when a materials database importer, finite-element pre-processor, laboratory LIMS, certification checklist, failure-analysis notebook, or CAD plugin must convert fracture toughness 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 stress or modulus tools when a product pipeline needs several mechanical measure families, or call it alone when search traffic is specifically for fracture toughness conversion—megapascal root meter, ksi root inch, pascal root meter, N per millimetre to the three-halves, and related symbols—rather than a general unit switchboard.
Integration use cases
Lab LIMS and standards compliance
Import N/mm^{3/2} or Pa·√m instrument logs into MPa·√m reports required by ASTM or ISO workflows with a deterministic prepaid API contract.
Technical questions
Which fracture toughness units does this converter support?
Pa_m05 (Pa·√m), kPa_m05 (kPa·√m), MPa_m05 (MPa·√m), GPa_m05 (GPa·√m), ksi_in05 (ksi·√in), psi_in05 (psi·√in), and N_mm15 (N/mm^{3/2}). Full names and common symbols are accepted; unknown units raise invalid_input.