Rabbit gestation calculator
A doe mated on 1 March 2026 is due to kindle on 1 April 2026, 31 days later, the textbook average for domestic rabbits. Plan the nest box and kit checks around that date. Free in your browser.
- Free
- Runs in your browser
- No sign-up
- Your data stays on your device
Run — free
Worked example
- Date
- 2026-03-01
- Due date
- 2026-04-01
- Gestation days
- 31
Domestic rabbit pregnancy is short, intense, and easy to miss on a busy calendar: from a confirmed mating to kindling, the conventional average is thirty-one days. Meat-rabbit barns, 4-H rabbitries, and backyard breeders use that offset every week to put a nest box in the cage, watch the doe for nest-building, and staff kit checks before the first kit arrives. This rabbit gestation calculator takes one breeding date in strict YYYY-MM-DD form, adds the textbook thirty-one-day Oryctolagus cuniculus average with pure civil-calendar arithmetic, and returns the estimated due date. Use it for breeding-book checks, nest-box schedules, and automation that needs a transparent thirty-one-day baseline.
What 31-day rabbit gestation means and how kindling is dated
Rabbit gestation is counted from the day the doe is mated, not from an estimated ovulation a few hours later and not from a last-estrus calendar the way human obstetric dating uses last menstrual period. Does are induced ovulators: a successful mating typically triggers ovulation within about ten hours, so the breeding-book date is the practical start of pregnancy.
Extension tables and commercial rabbitry manuals almost universally quote thirty-one days as the average for Oryctolagus cuniculus, with a typical live range of about twenty-eight to thirty-five days around that mean; most domestic kindlings cluster at thirty to thirty-two. This rabbit gestation calculator implements that published average as a fixed civil-day offset: it parses the breeding date, validates that the day exists on the Gregorian calendar including leap February twenty-ninth, adds exactly thirty-one whole days, and emits the resulting calendar day as the estimated due date.
The arithmetic never consults a wall clock, never reads the host timezone, and never calls a Date constructor, so a breeding day near a daylight-saving boundary cannot shift the kindling day. The only required field is date, a strict YYYY-MM-DD string naming the mating day recorded in the breeding book.
Where a rabbit gestation calculator earns its keep in the rabbitry
Kindling planners and meat-rabbit barns often need a first-pass due date the moment a keeper records a successful mating, before palpation confirms pregnancy. Embedding this calculator gives a transparent thirty-one-day baseline with a published formula that 4-H students and product copy can quote without reverse-engineering a date library. Nest-box practice is the everyday reason the number matters: most keepers add the box around day twenty-seven or twenty-eight so the doe can pull fur without soiling it for weeks, and a reliable kindling day is how that reminder is scheduled.
Prefer palpation and veterinary dating when clinical policy requires it, and treat the thirty-one-day output as the conventional average it has always been: simple, explainable, and deterministic.
What you can do with it
Nest-box and kindling-watch reminders
Turn each confirmed mating date into an expected kindling day so the cage gets a nest box around day twenty-seven and kit checks are staffed on time.
4-H and backyard breeding worksheets
Project kindling from a breeding-book row so students and hobby keepers can plan cages, feed, and foster does around the thirty-one-day average.
Breeding-book archives and automation
Recompute expected kindling columns from stored YYYY-MM-DD mating dates without timezone-sensitive Date libraries.
FAQ
How is the expected kindling date computed?
The calculator adds exactly 31 whole civil days to the breeding (mating) date using Gregorian month lengths and leap years.
Why 31 days instead of a month or 28–35 days?
Thirty-one days is the conventional average gestation for domestic rabbits used in rabbitry manuals. Live kindling often falls between 28 and 35 days; this tool returns the textbook mean, not a custom range.
Does the calculator handle leap years and year boundaries?
Yes. Month lengths and Gregorian leap days are applied in pure civil-calendar arithmetic, so a breeding date of 2024-02-29 or a mating late in December rolls correctly into the next month or year.
When should I put the nest box in for a pregnant doe?
Most keepers add it around day 28 after mating, a few days before the due date. That gives the doe time to build the nest and pull fur without soiling the box for weeks.
Is the rabbit due date exact for my doe?
No. It is a planning estimate: real gestations run roughly 28 to 35 days and vary with the doe, breed, litter size and season. Palpation from around day 10 or a veterinarian can confirm and refine it.
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/rabbit-gestation \
-H "Authorization: Bearer $KIT_KEY" \
-H "Content-Type: application/json" \
-d '{"date":"2026-03-01"}'const res = await fetch("https://api.kit.forhosting.com/bio/rabbit-gestation", {
method: "POST",
headers: {
"Authorization": `Bearer ${process.env.KIT_KEY}`,
"Content-Type": "application/json"
},
body: JSON.stringify({
"date": "2026-03-01"
})
});
const { task_id } = await res.json();import os, requests
res = requests.post(
"https://api.kit.forhosting.com/bio/rabbit-gestation",
headers={"Authorization": f"Bearer {os.environ['KIT_KEY']}"},
json={
"date": "2026-03-01"
},
)
task_id = res.json()["task_id"]<?php
$res = file_get_contents("https://api.kit.forhosting.com/bio/rabbit-gestation", false, stream_context_create([
"http" => [
"method" => "POST",
"header" => "Authorization: Bearer " . getenv("KIT_KEY") . "\r\nContent-Type: application/json",
"content" => '{"date":"2026-03-01"}',
],
]));
$task = json_decode($res, true);body := bytes.NewBufferString(`{"date":"2026-03-01"}`)
req, _ := http.NewRequest("POST", "https://api.kit.forhosting.com/bio/rabbit-gestation", body)
req.Header.Set("Authorization", "Bearer "+os.Getenv("KIT_KEY"))
req.Header.Set("Content-Type", "application/json")
res, _ := http.DefaultClient.Do(req)Example request
{
"date": "2026-03-01"
}Example response
{
"task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
"type": "bio.rabbit_gestation",
"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
When the breeding date is missing or is not a real calendar day, the task fails with invalid_input instead of inventing a due date.
What 31-day rabbit gestation means and how kindling is dated
Aliases breeding_date, bred_date, and mated_date map to the same parse path so rabbitry forms can keep their preferred names. The response echoes the normalized breeding date, reports due_date in the same ISO shape, states gestation_days as thirty-one, and restates the formula so a user interface can print the rule next to the answer. This is a planning estimate, not a veterinary diagnosis: individual does, breeds, litter size, and season vary, and a veterinarian or rabbitry software may refine the window after abdominal palpation around day ten to fourteen.
Input contract, validation, response shape, and deterministic errors
Month must fall between one and twelve; day must be real for that month, so values such as two thousand twenty-six February thirtieth are rejected because February never has thirty days, and two thousand twenty-three February twenty-ninth is rejected because that year is not a leap year under the Gregorian rule. A late-December mating rolls into January of the next year without a timezone surprise. Do not send timestamps with a time of day, time zones, or a custom gestation length to this capability—those belong to other tools; this page is intentionally the textbook thirty-one-day rabbit gestation transform only. POST a JSON object whose required field date is a string matching four digits, hyphen, two-digit month, hyphen, two-digit day. Missing date, null, empty string, non-string objects, and strings that fail that pattern all throw invalid_input naming the field and the expected shape. On success the body always includes date, due_date, gestation_days, and formula; optional null fields are never padded in. Failed validation is not billed, so you can probe hostile or incomplete payloads without spending prepaid balance.
Technical questions
Which input fields are required?
Only date (YYYY-MM-DD). Aliases breeding_date, bred_date, and mated_date are accepted. Missing, empty, or impossible calendar days return invalid_input and are not billed.
What does the rabbit gestation calculator cost?
The browser widget is free. API calls use prepaid KIT balance at $0.002 per successful task; invalid input is not charged.