Animal Gestation Calculator
Enter the breeding or conception date and pick a species to estimate the due date and the normal birthing range — for dogs, cats, cattle, horses, goats and more.
Knowing roughly when an animal is due helps you prepare a clean, quiet birthing area, arrange veterinary support, and watch for the signs of labour at the right time. Each species carries its young for a fairly predictable number of days, so counting forward from the breeding date gives a reliable estimate. This calculator uses typical average gestation lengths and shows a normal range around the due date, since the exact day varies with breed, litter size and the individual.
How the due date is calculated
Add the species' average gestation length to the breeding or conception date. Because births naturally fall a few days either side of the average, the calculator also shows a range.
Range = Due date ± a few days (species-dependent)
| Species | Average gestation |
|---|---|
| Dog | 63 days (about 9 weeks) |
| Cat | 65 days |
| Cow / cattle | 283 days (about 9¼ months) |
| Horse | 340 days (about 11 months) |
| Pig | 114 days (3 months, 3 weeks, 3 days) |
| Sheep | 147 days |
| Goat | 150 days |
| Rabbit | 31 days |
Worked example
A dog bred on 13 July has an average 63-day gestation:
| Due date = 13 July + 63 days | 14 September |
| Normal whelping range | ~12–16 September |
Why the exact day varies
Averages hide real variation. In dogs, timing measured from the mating date can swing by a week because sperm can survive for days and eggs need time to mature; measured from ovulation it's far more precise. Litter size matters too — larger litters often arrive a little earlier. Cattle and horse gestations vary with breed and even the sex of the offspring. Treat the due date as the middle of a window, not a fixed appointment, and get veterinary advice as the time approaches.