Animal Gestation Calculator (Due Date for Pets and Livestock)
Choose the species and enter the breeding date to estimate the birth date.
Your numbers
Your results
Animal Gestation Calculator (Due Date for Pets and Livestock) by TheCalcTools
How the Animal Gestation Calculator (Due Date for Pets and Livestock) works
Due date = breeding date + the species’ average gestation length. The Merck Veterinary Manual lists, for example, 65 days for cats, 114 for pigs (three months, three weeks and three days), 150 for goats and sheep, and 335 to 342 for horses.
Individual animals vary by several days (cattle by ±7 to 10 days, horses by weeks), and breed, litter size and season matter. Watch for signs of labour from a week before the date.
The formula
Worked example
Using the default values shown in the calculator:
| Species and average gestation | Cat (65 days) |
|---|---|
| Breeding date | 2026-08-20 |
| Today | 2026-10-17 |
- A cat bred on 20 August 2026 is due around Saturday, 24 October 2026.
Result:
| Estimated due date | Saturday, 24 October 2026 |
|---|---|
| Gestation length used (days) | 65 |
| Progress today | 89% (day 58) |
| Days until the due date | 7 |
Frequently asked questions
How long is a horse pregnant?
About 11 months: 335 to 342 days on average, though healthy foals arrive from about 320 to 370 days.
How long is a cat pregnant?
About 65 days, roughly 9 weeks.
Sources and further reading
- Merck Veterinary Manual: Approximate gestation periods
- Wikipedia: List of mammalian gestation durations
Related calculators
More in Pets & Animals · All calculators
This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.