How the calculator works
Choose an animal, the closest available breed, and the date she was bred or inseminated. The calculator adds elapsed days to that date: breeding is day zero. For cattle, the general reference is 283 days; goats use 150, sheep 147, horses 340, and pigs 114. Breed selections change the reference where cited values are available.
The average date is a planning estimate. Goats, horses, and pigs use their cited species ranges. Cattle windows use the selected average plus or minus 9 days, about twice the Angus study’s 4.69-day standard deviation; sheep windows shift the 144–152-day range with the breed average. These cattle and sheep window adjustments are our stated methods.
If she stayed with the male, enter the entire exposure period to preserve the uncertainty in your record. Reverse mode works backward from a birth date. The return-to-heat line uses the cited cycle lengths as an observation prompt, not proof of pregnancy. Keep the average, window, and actual observations separate, and confirm pregnancy with your veterinarian.
Gestation at a glance
| Species | Average | Normal range | About | Source |
|---|---|---|---|---|
| Cattle (beef average) | 283 days | 274–292 days (±9) | 9.3 months | MS State Extension |
| Goat | 150 days | 145–155 days | 4.9 months | Merck Veterinary Manual |
| Sheep | 147 days | 144–152 days | 4.8 months | NMSU Extension |
| Horse | 340 days | 320–370 days | 11.2 months | Nebraska Extension |
| Pig | 114 days | 111–117 days | 3.7 months | UNH Extension |
See every breed, heat cycle, source, and window method in the livestock gestation chart.
Tools for the season
Cow calculator
Calving dates for beef and dairy breeds.
Open cow calculatorGoat calculator
Kidding dates and the late-pregnancy milestone.
Open goat calculatorSheep calculator
Lambing dates for general, prolific, and fine-wool breeds.
Open sheep calculatorHorse calculator
Foaling estimates and the prematurity marker.
Open horse calculatorCow chart
A printable breeding-to-calving reference.
Open cow chartHerd planner
Keep, print, export, or share a due-date list.
Open herd plannerBreeding guides
Plain-language explanations with linked sources.
Open breeding guides