What this calculator does
Pet gestation & due date works out expected birth date range for a common pet or farm animal, from the breeding date. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaDue date = breeding date + average gestation length (± typical range)
The inputs explained
| Field | What to enter |
|---|---|
| Animal | Choose from Dog, Cat, Rabbit, Guinea pig, Hamster, Horse, Cow, Goat, Sheep. |
| Breeding / mating date | A calendar date. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with animal
Every other input is held at the calculator’s starting values. Select any row to load that scenario.
How the answer changes with animal
| Animal | Expected due date | Likely window | Average gestation length |
|---|---|---|---|
| Dog | 6 Oct 2026 | 1 Oct 2026 – 11 Oct 2026 | 63 days |
| Cat | 7 Oct 2026 | 6 Oct 2026 – 8 Oct 2026 | 64 days |
| Rabbit | 4 Sep 2026 | 1 Sep 2026 – 8 Sep 2026 | 31 days |
| Guinea pig | 8 Oct 2026 | 2 Oct 2026 – 15 Oct 2026 | 65 days |
| Hamster | 22 Aug 2026 | 20 Aug 2026 – 25 Aug 2026 | 18 days |
| Horse | 10 Jul 2027 | 20 Jun 2027 – 9 Aug 2027 | 340 days |
| Cow | 14 May 2027 | 10 May 2027 – 18 May 2027 | 283 days |
| Goat | 1 Jan 2027 | 27 Dec 2026 – 6 Jan 2027 | 150 days |