Cow Gestation Calculator
Estimate how many days are left until a cow is due to calve, based on days since breeding and the typical gestation length for her breed.
What this calculator does
The Cow Gestation Calculator estimates how many days remain until a cow is due to calve, based on how many days have passed since breeding or artificial insemination (AI) and her breed’s typical gestation length.
The method it uses
Average bovine gestation is commonly cited as around 283 days, but it varies somewhat by breed — dairy breeds like Holstein and Jersey tend to run a little shorter (around 279 days), while some beef breeds such as Hereford (around 285 days) and Brahman (around 292 days) run longer. This calculator subtracts the days already elapsed from the expected total for the selected breed.
It also reports how many weeks pregnant the cow is and what percentage of the pregnancy is complete.
A note on accuracy
Individual cows vary around these breed averages, and factors like the calf’s sex and the dam’s age can shift the actual calving date by several days in either direction. Use this tool for general herd planning purposes rather than a precise due-date guarantee, and consult a veterinarian for confirmed pregnancy staging.