Frequency period converter
A 50 Hz mains waveform repeats every 0.02 seconds, and a clock edge every microsecond means one megahertz. Enter either the frequency in hertz or the period in seconds and get the other one back. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Frequency
- 50
- Period
- 0.02
- Solved
- period
- Unit frequency
- Hz
- Unit period
- s
Every periodic signal has a frequency and a period that are strict reciprocals of each other: the period T is the time for one full cycle, and the frequency f is how many cycles occur per second, so T equals one over f and f equals one over T. This capability is a focused frequency period converter for electronics, lab work, and signal-processing workflows. Send frequency in hertz to obtain period in seconds, or send period in seconds to obtain frequency in hertz. Zero input is rejected with a clear invalid input error because division by zero is undefined.
Frequency, period, and the reciprocal identity
In continuous-time signals and AC circuit theory, frequency f is measured in hertz (cycles per second) and period T is measured in seconds per cycle. They are linked by the elementary identity T equals one divided by f, and equivalently f equals one divided by T. If a mains waveform runs at fifty hertz, one cycle lasts zero point zero two seconds; if a clock edge repeats every one microsecond, the frequency is one megahertz.
Negative values are rejected because ordinary signal frequency and period are positive scalars. The response always echoes both frequency and period after conversion, labels which field was solved, and records the formula string used so UIs can show T equals one over f or f equals one over T without re-deriving the identity.
What you can do with it
Mains and clock rate checks
Convert 50 Hz or 60 Hz line frequency to period in seconds, or convert a measured clock period on an oscilloscope back to frequency in hertz for firmware and power documentation.
FAQ
Can I send both frequency and period?
No. Provide exactly one of frequency or period and omit the unknown.
Is the frequency period converter free?
The browser tool runs free on your device.
How long is one cycle of 50 Hz mains?
One cycle lasts 0.02 seconds, because the period is one divided by the frequency. Enter 50 as the frequency and the converter returns the period in seconds, along with the frequency you entered.
Can I enter kilohertz, megahertz or milliseconds?
No. The converter always works in hertz and seconds, so convert first: a period of one microsecond is one millionth of a second, and its frequency comes back in hertz as one megahertz.
Why are zero and negative values refused?
A zero frequency or period would mean dividing by zero, which has no answer, and ordinary signals never have a negative frequency or period. The converter stops with a clear message instead of showing a meaningless result.
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/elec/frequency-period \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"frequency":50,"f":1}'const res = await fetch("https://api.kit.forhosting.com/elec/frequency-period", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"frequency": 50,
"f": 1
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/elec/frequency-period",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"frequency": 50,
"f": 1
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/elec/frequency-period", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"frequency":50,"f":1}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"frequency":50,"f":1}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/elec/frequency-period", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"frequency": 50,
"f": 1
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "elec.frequency_period",
"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
Frequency, period, and the reciprocal identity
This converter accepts exactly one of the two quantities so the request is unambiguous: provide frequency when you know the rate and need the time between cycles, or provide period when you measured a duration on a scope and need the corresponding rate. Units are fixed to hertz and seconds for a stable API contract; convert kilohertz, megahertz, or milliseconds at the edge of your app before calling. Non-finite values and empty payloads also fail validation. Identical inputs always produce identical JSON because the path is pure floating-point arithmetic with no network, no random seed, and no wall clock.
Inputs, zero rejection, aliases, and reading the result
Provide exactly one side; if both appear, the engine returns invalid input so you do not silently trust a pair that disagrees after rounding. If neither appears, the engine asks for exactly one field. Zero frequency cannot produce a period of one over f, and zero period cannot produce a frequency of one over T, so both cases raise invalid input with an explicit division-by-zero message that validation suites can match. Use frequency alone when sizing timers from a known clock rate; use period alone when a datasheet lists pulse width or cycle time and you need hertz for a PLL or filter design. Send a JSON object with either frequency or period as a finite number or numeric string. Common aliases are accepted for convenience: f, hz, freq, and frequency_hz map to frequency; T, t, seconds, and period_s map to period. On success the body includes frequency in hertz, period in seconds, solved set to frequency or period, formula set to the matching reciprocal string, method fixed to t_equals_1_over_f, and unit labels unit_frequency and unit_period for display. Missing objects, non-numeric strings, and magnitudes above the published bound all fail with invalid_input and are not charged on the prepaid path.
API usage, pricing, lab workflows, and practical limits
Call the free in-browser frequency period converter for quick bench checks, lecture demos, and mental-math verification without opening a calculator app or spreadsheet. Authors shipping SDKs can map frequency and period into labeled form fields with unit suffixes Hz and s, and surface the formula field next to the solved value so students see the reciprocal identity they are applying. The product does not convert angular frequency omega equals two pi f, does not estimate duty cycle, and does not replace a spectrum analyzer; it answers one search intent cleanly: convert frequency to period and period back to frequency with honest errors on zero input. Use the prepaid API when firmware generators, education platforms, test harnesses, or documentation pipelines need a stable contract under KIT balance at $0.002 per successful item; validation failures never consume balance after the engine rejects the request. Pair this endpoint with wave-speed tools when you also know propagation velocity and need wavelength, or with RC and timer calculators when the next step is choosing components for a target frequency. Keep magnitudes within the documented bound for Worker isolate safety, and normalize scientific prefixes in your client before the call so the API always sees raw hertz and seconds.
Integration use cases
Lab and education workflows
Students and instructors convert between f and T while learning periodic signals, with a clear invalid_input error when someone submits zero by mistake.
CI and API pipelines
Generators and test harnesses call a deterministic prepaid endpoint to fill frequency and period fields in reports without reimplementing the reciprocal in every language.
Technical questions
How do I convert frequency to period?
Send JSON with frequency set to a positive value in hertz (for example frequency: 50). The response includes period in seconds using T = 1 / f, plus frequency echoed back.
How do I convert period to frequency?
Send JSON with period set to a positive duration in seconds (for example period: 0.02). The response includes frequency in hertz using f = 1 / T.
What happens if frequency or period is zero?
The request fails with invalid_input. Division by zero is undefined for T = 1 / f and f = 1 / T; zero inputs are rejected and not charged.