Animal Gestation Calculator

Cow Gestation Calculator

Last updated

A cow's gestation period is about 283 days, or roughly 9 months and 1 week, though it ranges from 279 to 292 days depending on breed and individual animal.

Calculate a calf due date

What do you know?

Bull calves are typically carried slightly longer than heifer calves.

Estimated calving date

Sunday 8 August 2027

Earliest

4 Aug 2027

Latest

17 Aug 2027

283 days remaining0% complete

0 of 283 days elapsed

Milestone timeline

Key Cow pregnancy milestones with calculated calendar dates
DayMilestoneDate
30Pregnancy check by ultrasound28 Nov 2026
223Dry off (60 days pre-calving)9 Jun 2027
253Pre-calving vaccinations9 Jul 2027
273Move to calving pen29 Jul 2027
283Expected calving8 Aug 2027

What to do next

How to use the cow gestation calculator

  1. 1. Choose what you know. Enter the breeding date to get a due date, or switch to the target due date mode to work backwards to the breeding date you need.
  2. 2. Refine the inputs. Pick the breed so the calculator uses the right average gestation length.
  3. 3. Plan around the range. Use the earliest and latest dates and the milestone timeline to schedule checks, feed changes and preparation of the calving area.

How long is a cow's gestation period?

The average is 283 days from breeding to calving, about 9 months and 1 week. Anything between 279 and 292 days is normal, and a typical litter is 1 calf. Treat the calculated date as the middle of that window rather than a fixed appointment.

Cow gestation table: breeding date to calving date

Breeding dates one week apart with the matching calving date at 283 days.

Twelve sample Cow breeding dates and their calculated due dates
Breeding dateExpected calving date
29 Oct 20268 Aug 2027
5 Nov 202615 Aug 2027
12 Nov 202622 Aug 2027
19 Nov 202629 Aug 2027
26 Nov 20265 Sept 2027
3 Dec 202612 Sept 2027
10 Dec 202619 Sept 2027
17 Dec 202626 Sept 2027
24 Dec 20263 Oct 2027
31 Dec 202610 Oct 2027
7 Jan 202717 Oct 2027
14 Jan 202724 Oct 2027

How breed changes the calving date

Selecting a breed swaps the average the calculator uses, which can move the calving date by more than a week.

Cow breeds and their average gestation length in days
BreedAverage daysDifference
Average283—
Holstein279-4 days
Jersey279-4 days
Angus281-2 days
Hereford285+2 days
Simmental287+4 days
Charolais287+4 days
Brown Swiss290+7 days
Brahman292+9 days

Working backwards from a target calving date

If you want calfs on the ground in a particular week, switch the calculator to target date mode and enter the date you are aiming for. It subtracts 283 days to give the breeding date to book, plus the earliest and latest service dates that still land inside your window.

Cow gestation calculator FAQs

How do I calculate a cow due date?

Enter the breeding or mating date and the calculator adds the average cow gestation of 283 days. It also shows the earliest (279 days) and latest (292 days) dates that are still normal.

Should I use the first or last mating date?

If mating happened over several days, run the calculator for the first and the last date. The calf is most likely to arrive between the earliest result of the first date and the latest result of the last date.

Can I work out when to breed for a target cow due date?

Yes. Switch to target due date mode and enter the date you want; the calculator subtracts 283 days to give the breeding date, plus the earliest and latest breeding dates that still fit.

How accurate is the cow due date calculator?

It gives a planning estimate from published averages. Most births fall inside the 279–292 day window shown, but ask a vet to confirm the pregnancy and check anything outside that range.

Does the breed change the cow due date?

It can. Pick the breed in the calculator and it uses that breed's average instead of the species average, which moves the due date by a few days for some breeds.

More gestation pages

Livestock gestation chart