Animal Gestation Calculator
Choose the species and enter the breeding date. The calculator adds the average gestation length and shows the earliest and latest dates in the normal range.
Result
- Earliest in the normal range
- Wednesday, October 21, 2026
- Latest in the normal range
- Thursday, October 29, 2026
- Average gestation
- 283 days
- In weeks
- 40 weeks and 3 days
Average gestation by species
| Animal | Average | Normal range |
|---|---|---|
| Cow | 283 days | 279 to 287 days |
| Horse | 340 days | 320 to 370 days |
| Goat | 150 days | 145 to 155 days |
| Sheep | 147 days | 144 to 152 days |
| Pig | 114 days | 112 to 116 days |
| Dog | 63 days | 58 to 68 days |
| Cat | 65 days | 63 to 67 days |
| Rabbit | 31 days | 28 to 35 days |
| Alpaca | 345 days | 335 to 365 days |
Gestation length varies with breed, litter size and the individual animal. Use the range for planning and consult a veterinarian about the pregnancy.
Formula
- Due date = breeding date + average gestation length
- Cow 283 days · Horse 340 · Goat 150 · Sheep 147 · Pig 114 · Dog 63 · Cat 65 · Rabbit 31
How the Animal Gestation Calculator works
Gestation is the time from conception to birth. Each species has a typical length, and the due date is found by counting that many days forward from the breeding date.
Averages hide real variation. Beef and dairy breeds of cattle differ by several days, and mares can foal weeks either side of the average. That is why the calculator also shows a normal range.
Worked example
A cow bred on January 15, 2026 is due 283 days later, on October 25, 2026. The normal range runs from October 21 to October 29.
Frequently asked questions
How long is a cow pregnant?
About 283 days, or a little over nine months. Most calves arrive between 279 and 287 days.
How long is a dog pregnant?
About 63 days from ovulation, with a normal range of roughly 58 to 68 days from breeding.
How long is a pig pregnant?
About 114 days, often remembered as three months, three weeks and three days.
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Calculations run in your browser and nothing you enter is sent to a server. Results are provided for general information. Check critical figures independently before relying on them.