How to use
- Choose the animal. For another species, choose “Other” and type the gestation length in days.
- Enter the breeding or insemination date. With several services, use the last one.
- Read the expected due date.
How it works
Due date = breeding date + average gestation length. The averages used:
| Animal | Days |
|---|---|
| Cow | 283 |
| Mare | 340 |
| Ewe | 147 |
| Goat | 150 |
| Sow | 114 |
| Rabbit | 31 |
For dogs there is a separate dog pregnancy calculator.
Example
A cow bred on 1 March 2026:
- 1 March + 283 days: 244 days take you to 31 October, and 39 more to 9 December;
- expected calving: 9 December 2026, about 40.4 weeks later.
A sow served on 10 January 2026 is due on 4 May 2026 (+114 days).
Tips and common mistakes
- Count from the date of breeding, not the date the animal was turned in with the male if they ran together for weeks. In that case calculate for the first and last possible dates.
- Get the calving or foaling area ready a week or two before the date.
- A due date is an average. Ask your vet when an animal goes well past it or shows signs of trouble.