Permittivity converter
One farad per metre is 1000000000000 picofarads per metre, and a dielectric constant turns into F/m when multiplied by the vacuum permittivity of 8.8541878128 × 10⁻¹² F/m. Switch between the five units datasheets mix. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Value
- 1
- Source unit
- F/m
- Target unit
- pF/m
- Result
- 1,000,000,000,000
- From label
- farad per metre
- To label
- picofarad per metre
- F per m
- 1
An electric permittivity converter turns a quantity written in one permittivity unit into another without hunting conversion tables, CODATA footnotes, or spreadsheet macros.
Supported units and how the conversion is computed
The converter accepts five permittivity families under stable canonical codes: F/m for the SI farad per metre (absolute electric permittivity ε), uF/m for the microfarad per metre (ASCII form; Greek mu micro symbols are also accepted), nF/m for the nanofarad per metre, pF/m for the picofarad per metre, and relative for dimensionless relative permittivity ε_r also known as the dielectric constant.
Absolute multiples follow SI engineering standards: one microfarad per metre is exactly one millionth of a farad per metre, one nanofarad per metre is one billionth, and one picofarad per metre is one trillionth. Relative permittivity maps through the fixed vacuum constant ε₀ equals 8.8541878128 times ten to the minus twelve farads per metre (CODATA 2018), because absolute permittivity equals relative permittivity times ε₀.
Because the intermediate is always farads per metre, 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. Capacitance, inductance, permeability, and loss-tangent units are intentionally out of scope so RF, dielectrics, and materials users get predictable permittivity-only results under one clear convention.
Where it helps with datasheets and design notes
Use the free in-browser permittivity converter when you need a quick farads-per-metre to relative permittivity, relative to picofarads-per-metre, or nanofarads-per-metre to microfarads-per-metre check while reading a dielectric datasheet, coaxial cable note, PCB laminate table, capacitor design guide, or electromagnetics 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 students, technicians, and engineers expect on paper.
What you can do with it
Dielectric materials and PCB laminates
Convert relative permittivity on datasheets to absolute F/m or pF/m so stack-up tools, impedance calculators, and materials databases share one SI view without hand-written ε₀ factors.
RF, coax, and microwave design
Normalize picofarads per metre and relative dielectric constants in cable specs, transmission-line models, and matching notes when drawings mix absolute and relative labels.
FAQ
Which permittivity units does this converter support?
Farads per metre (F/m), microfarads per metre (uF/m or µF/m), nanofarads per metre (nF/m), picofarads per metre (pF/m), and relative permittivity (relative, ε_r, dielectric constant).
How is relative permittivity related to farads per metre?
Absolute permittivity ε equals relative permittivity ε_r times vacuum permittivity ε₀.
What happens if I send an unknown unit?
The message names the field and lists supported units. Validation failures are not charged.
Is the permittivity converter free?
The browser tool runs free on your device.
Does it also convert capacitance or loss tangent?
No. It handles permittivity only. Capacitance, inductance, magnetic permeability and loss tangent are left out on purpose, so every result stays within one clear convention for dielectric work.
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/permittivity \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"value":1,"from":"F/m","to":"pF/m"}'const res = await fetch("https://api.kit.forhosting.com/conv/permittivity", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"value": 1,
"from": "F/m",
"to": "pF/m"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/conv/permittivity",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"value": 1,
"from": "F/m",
"to": "pF/m"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/conv/permittivity", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"value":1,"from":"F/m","to":"pF/m"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"value":1,"from":"F/m","to":"pF/m"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/conv/permittivity", 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": "F/m",
"to": "pF/m"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "conv.permittivity",
"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
Friendly aliases such as farads per meter, picofarads per metre, epsilon_r, er, dielectric constant, and absolute permittivity are normalized case-insensitively so forms and APIs can pass either short codes or full names. Every request multiplies the input value by the exact farads-per-metre factor for the source, then divides by the farads-per-metre 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 permittivity in modeling pipelines; 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 f_per_m quantity in farads per metre, the fixed epsilon_0 constant used for relative links, the dimensionless factor from source to target, a short formula line suitable for UI display, the method tag permittivity_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. Picofarad-scale results and relative-scale results share the same code path, so extreme magnitude pairs remain well-defined as long as IEEE double precision can represent the intermediate farads-per-metre product.
Browser use, API pricing, and everyday workflows
Switch to the prepaid API when an electronics CAD plugin, materials database, microwave design tool, sensor calibration pipeline, physics homework checker, or instrumentation service must convert permittivity 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 capacitance or parallel-plate calculators when a product pipeline needs both absolute ε and geometry-based C, or call it alone when search traffic is specifically for permittivity conversion—farads per metre, relative permittivity, picofarads per metre—rather than a general unit switchboard.
Integration use cases
Lab metrology and homework checkers
Convert F/m through relative ε_r for precision measurements and class problems with a prepaid, deterministic API and clear invalid_input on unknown units.
Technical questions
How do I convert 1 farad per metre to picofarads per metre?
Send JSON with value: 1, from: "F/m", to: "pF/m". The response result field is 1e12, plus an f_per_m intermediate and a readable formula.