Animal Gestation Calculator
Calculate the estimated due date for any livestock or pet.
Enter the conception date and select from cow, horse, sheep, pig, goat, dog, cat, and more.
Animal Gestation Calculator
Gestation is the period from conception (fertilization) to birth. Each species has a characteristic gestation length shaped by the animal’s size, metabolism, and offspring development needs.
Average gestation periods by species:
| Species | Average Gestation | Range |
|---|---|---|
| Hamster | 16 days | 15–18 days |
| Rabbit | 31 days | 28–35 days |
| Cat | 63 days | 58–67 days |
| Dog | 63 days | 57–70 days |
| Pig | 114 days | 110–120 days |
| Goat | 150 days | 145–155 days |
| Sheep | 147 days | 140–160 days |
| Guinea Pig | 68 days | 59–72 days |
| Cow (cattle) | 283 days | 276–295 days |
| Donkey | 365 days | 350–380 days |
| Horse (mare) | 335 days | 320–362 days |
| Llama | 350 days | 330–370 days |
| Alpaca | 345 days | 330–360 days |
Important notes:
- These are average values — individual animals vary
- Breed differences can affect gestation: miniature horse breeds may be shorter than 320 days; large breeds of dogs (Great Dane) tend toward 63–65 days
- Twins or multiples can sometimes shorten gestation slightly in cattle and sheep
- Stress, nutrition, and management all affect actual birth timing
Using this calculator: Enter the confirmed conception (or breeding/service) date. If the exact mating date is unknown, the estimated due date is still useful as a planning window. Most veterinarians recommend monitoring closely during the last 10% of gestation.
Veterinary note: If an animal is overdue by more than 7–10% of its expected gestation, consult a veterinarian immediately. Prolonged gestation can indicate fetal distress, malpresentation, or other complications requiring intervention.