Animal Gestation Calculator
Find the expected due date for cows, horses, goats, sheep, pigs, rabbits and other animals from the breeding date.
About the Animal Gestation Calculator
Choose the species and enter the breeding date. The calculator gives the expected due date and the normal range around it.
Gestation lengths are averages: cattle about 283 days (9 months), horses about 340 days (11 months), goats 150, sheep about 147, pigs 114 ('3 months, 3 weeks and 3 days'), rabbits 31 and llamas/alpacas about 11.5 months, per the Merck Veterinary Manual's table of approximate gestation periods. Individual animals vary by breed, age and number of young.
The formula
Due date = breeding date + average gestation days
Worked example
A cow bred on 1 January 2026
- Average gestation 283 days
- Due about 11 October 2026
- Normal range about 1 to 21 October
Questions people ask
How can I confirm pregnancy?
Ultrasound, palpation or blood tests by a vet, depending on species.
Why do horses vary so much?
Normal mare gestation ranges from about 320 to 370 days.