Cricket chirp thermometer
Count a cricket's chirps for one minute: 120 chirps means about 70 °F, following Dolbear's law from 1897, with the Celsius value alongside. A quick outdoor estimate for nature walks, summer camps and classrooms. Free in your browser.
- Free
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- Your data stays on your device
Run — free
Worked example
- Chirps per minute
- 120
- Fahrenheit
- 70
- Celsius
- 21.1111111111
A cricket chirp thermometer turns a backyard count into an estimate of the surrounding air temperature. Tree crickets and field crickets chirp faster as the air warms because the muscle contractions that produce each pulse are temperature-dependent, a relationship Amos Dolbear published in 1897 as Dolbear's law. This calculator accepts the number of chirps counted in one minute, applies the classic Fahrenheit identity fifty plus N minus forty over four, converts that result to Celsius with the exact linear scale, and returns both temperatures together with the formula. Zero is a valid rate and maps to forty degrees Fahrenheit; a negative or non-numeric chirp count is rejected as invalid input so a missing count never becomes a silent temperature.
What Dolbear's law means and how both scales are computed
Dolbear's law is the empirical rule that the chirp rate of a cricket tracks the air temperature around the insect. Amos Dolbear published the relationship in 1897 after timing the snowy tree cricket, and the form used in field guides ever since is T_F equals fifty plus N minus forty, all over four, where N is the number of chirps counted in one full minute. That identity is exactly the same as counting chirps for fifteen seconds and adding forty, because a fifteen-second count is N divided by four.
This cricket chirp thermometer implements the minute form first so the input is a single non-negative number, then converts the Fahrenheit estimate to Celsius with the exact linear identity T_C equals T_F minus thirty-two, times five ninths. One hundred twenty chirps per minute therefore give seventy degrees Fahrenheit and twenty-one point one one degrees Celsius. Forty chirps per minute give fifty degrees Fahrenheit and ten degrees Celsius, which is the intercept of the original law.
Zero chirps per minute is accepted as a rate and maps to forty degrees Fahrenheit; it is not treated as a missing value. The model is a linear field estimate, not a laboratory thermometer: species, humidity, wind, and whether the cricket is a snowy tree cricket or a field cricket all shift the slope a little.
Use the result as a rapid outdoor check, a classroom demonstration of a biological rate law, or an input to a notebook that already stores a chirp count, not as a replacement for a calibrated sensor.
Where a cricket chirp thermometer earns its keep
Nature-study classrooms and summer camps use a cricket chirp thermometer so learners can check an outdoor temperature against a living insect instead of only against a glass bulb, and so they can see that a biological rate is a function of temperature. Exam-prep generators need a deterministic oracle that marks wrong a negative or missing chirp count instead of silently returning forty degrees Fahrenheit, which is exactly what a buggy grader would invent if it treated a blank as zero without telling the student.
The calculator does not replace a calibrated thermometer for safety-critical work, does not fit a species-specific slope, and does not convert a fifteen-second count for you — send chirps per minute and treat the pair of temperatures as Dolbear's linear field estimate when you chain it into a journal or a lesson plan.
What you can do with it
Backyard and camp temperature checks
Count cricket chirps for one minute and turn that rate into air temperature in Fahrenheit and Celsius without a weather station.
FAQ
What happens if the chirp count is negative or missing?
The chirp count must be a non-negative number; failed validation is not billed.
Is a count of zero allowed?
Yes. Zero is a non-negative rate and maps to 40 °F (about 4.44 °C) under Dolbear's law. It is not treated as a missing field.
Can I count chirps for fifteen seconds instead of a minute?
Yes. Count for fifteen seconds and add 40 to get degrees Fahrenheit directly, or multiply that count by four and enter it as chirps per minute. Both routes give the same result.
How accurate is a cricket chirp thermometer?
It is a linear field estimate, not a lab thermometer. Species, humidity and wind shift the result a little, so use it as a quick outdoor check or classroom demonstration, not instead of a calibrated sensor.
Who discovered that crickets chirp faster when it is warmer?
Amos Dolbear published the rule in 1897 after timing the snowy tree cricket. It is known as Dolbear's law and is still the form used in field guides today.
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/bio/cricket-chirp-thermometer \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"chirps_per_minute":120}'const res = await fetch("https://api.kit.forhosting.com/bio/cricket-chirp-thermometer", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"chirps_per_minute": 120
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/bio/cricket-chirp-thermometer",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"chirps_per_minute": 120
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/bio/cricket-chirp-thermometer", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"chirps_per_minute":120}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"chirps_per_minute":120}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/bio/cricket-chirp-thermometer", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"chirps_per_minute": 120
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "bio.cricket_chirp_thermometer",
"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
Input contract, response fields, and validation errors
Zero is a valid non-negative number and is not rejected. The calculator does not identify the cricket species, does not correct for humidity, and does not accept a fifteen-second count as a separate field — multiply a fifteen-second count by four before you call if that is how you timed the insect. Keep requests small, pin the rounded temperatures in tests, and you get a reproducible cricket thermometer for homework, citizen-science logs, and edge workers without standing up a weather station of your own. POST a JSON body with one required non-negative finite number, chirps_per_minute, the count N of cricket chirps in sixty seconds. Short aliases work the same way: chirps, n, N, count, chirp_count, rate, and chirps_min. The field may arrive as a JSON number or as a numeric string; empty strings, missing keys, non-finite values, negatives, and magnitudes beyond one million chirps per minute fail with invalid_input naming the field. On success the body echoes chirps_per_minute after stable rounding, reports fahrenheit as fifty plus N minus forty over four, reports celsius as that Fahrenheit value converted with five ninths, and includes a formula string restating both identities. Example: chirps_per_minute one hundred twenty yields fahrenheit seventy and celsius twenty-one point one one one one one one one one one one one one. Failed validation is not billed; successful calls use prepaid KIT balance at the published $0.002 base price per item.
Where a cricket chirp thermometer earns its keep
Citizen-science notebooks and backyard phenology logs already store a chirp count; calling a tiny parse API turns that count into Fahrenheit and Celsius without opening a spreadsheet or mixing the fifteen-second shortcut with the per-minute form.
Integration use cases
Classroom Dolbear's-law homework
Let students submit a chirp count per minute and check both temperature scales against the T_F = 50 + (N − 40) / 4 identity.
Citizen-science and phenology logs
Convert stored chirp rates in a field notebook into reproducible °F and °C values that match the free browser widget.
Technical questions
How do I estimate temperature from cricket chirps?
Send a non-negative chirps_per_minute count N. The API returns T_F = 50 + (N − 40) / 4 and T_C = (T_F − 32) × 5/9.
I counted chirps for fifteen seconds. What should I send?
Multiply that fifteen-second count by four to obtain chirps per minute, then send chirps_per_minute. There is no separate 15-second field.
What does the cricket chirp thermometer cost?
The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.