Cattle Gestation Calculator

Enter the AI or bull breeding date to get the calving date, adjusted for breed, plus heat-check and dry-off dates.

The day the cow was bred or inseminated, or the day the bull went in.
For pasture breeding. Widens the window.

Loading calculator…

Cattle Gestation Calculator · HerdMath

How it works

Cattle gestation averages about 283 days, a little over 9 months. Breed makes a real difference: dairy breeds like Holsteins and Jerseys run shorter, and Continental and Brahman-influenced cattle run longer. Bull calves are often carried a day or two longer than heifer calves.

How to use it

Enter the AI date or the day the bull was put in. For pasture breeding, add the day the bull was pulled so you get the full calving window. Pick the breed, or the sire's breed for crossbred calves.

Reference chart

BreedAverage gestation
Average (most breeds)283 days
Angus281 days
Hereford285 days
Holstein279 days
Jersey279 days
Shorthorn282 days
Simmental289 days
Charolais289 days
Limousin289 days
Brown Swiss290 days
Brahman292 days

Frequently asked questions

How long is a cow pregnant?

About 283 days, just over 9 months. Most cows calve within about 10 days either side of the average for their breed.

Which breeds have the longest gestation?

Brahman and Brahman-cross cattle, along with Continental breeds like Brown Swiss, Simmental, Charolais and Limousin, often run 287–292 days. Holsteins and Jerseys are nearer 279 days.

When can you tell if a cow is pregnant?

A vet can usually confirm pregnancy by ultrasound from about 28–35 days after breeding, or by rectal palpation from about 35–45 days. Blood tests are another option from about 28–30 days.

How long after calving can a cow be bred?

Most producers aim to rebreed 60–90 days after calving to keep a calf every 12 months. The first heat often returns 30–60 days after calving.

Figures are typical values from university extension and breed-association guidance. Estimates only. Individual animals vary — confirm pregnancy and health questions with your veterinarian. Last reviewed 2026-09-18.