Pipe resonance calculator
A 0.5 m pipe open at both ends, with sound at 343 m/s, resonates at 343 Hz and then at 686, 1029, 1372 and 1715 Hz. Enter length, sound speed and whether one end is closed to list every mode with its wavelength. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Length
- 0.5
- Sound speed
- 343
- End condition: "open"
- Open
- Harmonics
- 5
- Calculation mode
- open_open
- Fundamental
- 343
- Wavelength fundamental
- 1
Air columns in pipes support standing sound waves at discrete frequencies set by length, the speed of sound in the medium, and whether each end is open or closed. Musicians, physics students, and instrument makers need the fundamental and the harmonic series without re-deriving open-pipe and closed-pipe formulas every time. This capability takes pipe length, sound speed, and an ends flag of open or closed, then returns the fundamental frequency, the fundamental wavelength, and a structured list of successive modes with frequency and wavelength for each. Zero length is rejected as invalid input because the classical formulas divide by length.
Open versus closed pipes and which frequencies appear
An ideal open pipe has pressure nodes at both ends, so the longest standing wave is half a wavelength along the tube: the fundamental frequency equals the speed of sound divided by twice the length, written f one equals v over two L. Higher modes pack integer numbers of half-wavelengths, giving the full harmonic series f n equals n times v over two L for n equals one, two, three, and so on.
A closed pipe has one closed end (a displacement node and a pressure antinode) and one open end, so the fundamental is a quarter wavelength: f one equals v over four L. Only odd multiples fit cleanly, so the spectrum is f equals one, three, five times the fundamental, often written f n equals open parenthesis two n minus one close parenthesis times v over four L. Search intent clusters around pipe resonance calculator, open pipe harmonics, closed pipe fundamental frequency, organ pipe frequencies, and standing wave in a tube.
People want numeric answers for a stated length and sound speed—classroom air near three hundred forty-three metres per second is common—not only a diagram of nodes and antinodes. Units stay consistent: metres with metres per second yield hertz; any coherent length and speed pair works if you keep the ratio. This product models ideal geometry without end correction, so it matches textbook problem sets that ignore the open-end correction factor of order pipe radius.
Practical use, pricing, limits, and delivery channels
Use the free in-browser pipe resonance calculator when checking homework on organ pipes, flute-like open tubes, clarinet-like closed tubes, or lab resonance-tube experiments that measure length for a known frequency. Pair length with a measured or assumed sound speed—room air near three hundred forty-three metres per second at about twenty degrees Celsius is a common classroom default—or chain from a speed-of-sound helper when temperature is the known quantity. Keep lengths positive and within ordinary laboratory scales so floating-point results stay well-conditioned; the engine also bounds extreme magnitudes for isolate safety.
Authors shipping SDKs can map the harmonics array directly into frequency tables for charts and flashcards.
What you can do with it
Homework and lab resonance-tube drills
Students and graders compute open-pipe and closed-pipe fundamentals and harmonics for given L and v, with a clear error when length is zero or ends is missing.
Wind-instrument and organ-pipe estimates
Quick structured frequencies for open and stopped pipes before applying craft-specific end corrections or bore models.
FAQ
How do I find the fundamental frequency of an open pipe?
The harmonics array lists higher modes as integer multiples.
How does a closed pipe differ from an open pipe?
With ends set to "closed", the fundamental is v/(4L) and only odd harmonics appear: 1×, 3×, 5× the fundamental. Open pipes use v/(2L) and all integer harmonics.
What happens if pipe length is zero?
Standing-wave formulas divide by length, so zero length is never a valid resonance geometry and is not charged.
Is the pipe resonance calculator free?
The browser tool runs free on your device.
Does this include open-end correction?
No. The model is ideal textbook geometry without end correction. Apply L_eff = L + 0.3d yourself if your lab or craft formula requires it, then send the effective length.
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/phys/pipe-resonance \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"length":0.5,"sound_speed":343,"ends":"open"}'const res = await fetch("https://api.kit.forhosting.com/phys/pipe-resonance", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"length": 0.5,
"sound_speed": 343,
"ends": "open"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/phys/pipe-resonance",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"length": 0.5,
"sound_speed": 343,
"ends": "open"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/phys/pipe-resonance", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"length":0.5,"sound_speed":343,"ends":"open"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"length":0.5,"sound_speed":343,"ends":"open"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/phys/pipe-resonance", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"length": 0.5,
"sound_speed": 343,
"ends": "open"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "phys.pipe_resonance",
"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
How this calculator validates input and builds the mode list
Optional harmonics is an integer from one to fifty that chooses how many successive modes to list; the default is five, which covers the fundamental plus the next four listed modes for open pipes, or the first five odd harmonics for closed pipes. Numeric strings that parse to finite numbers are accepted so forms and worksheets can pass values without an extra cast. Send a JSON body with required positive length, positive sound speed, and ends set to the string open or closed. Missing length, zero length, negative length, zero or negative sound speed, non-numeric strings, empty ends, and unknown ends values all fail with invalid_input before any frequency is returned, and failed validation is not charged. On success the response echoes length, sound speed, and ends, sets mode to open_open or closed_open, reports fundamental and wavelength_fundamental, and fills a harmonics array where each entry has index n starting at one, the musical harmonic number (equal to n for open pipes, equal to two n minus one for closed pipes), frequency in inverse time units consistent with your inputs, and the corresponding wavelength. Results are rounded to a stable decimal precision so the same input always yields the same JSON across JavaScript engines.
Practical use, pricing, limits, and delivery channels
Wire the endpoint into acoustics drills, wind-instrument demos, or lab scripts that already prefer explicit domain errors—such as rejecting zero length—over opaque widgets that cannot explain why a bad input was refused.
Integration use cases
Deterministic fixtures for acoustics tests
Pipelines and lesson platforms pin expected fundamental and harmonic lists from a pure oracle instead of reimplementing standing-wave formulas in every language.