Whelping Date Calculator for Dogs, Horses, Goats, Sheep, and Cattle

Last Reviewed: May 16, 2026. Built and reviewed by the BreederHQ Operations Team, working with active breeders and reproductive veterinarians.

Pick a species, enter a breeding date (or a progesterone-confirmed ovulation date if you have one for dogs), and this free calculator returns an estimated due date, a normal due window, and species-specific prep dates. It is a planning tool based on textbook gestation averages, not a veterinary decision tool. Real timing should come from your reproductive vet.

How to Use This Calculator

1 Pick the species. Gestation length and prep timing differ across dogs, horses, goats, sheep, and cattle. The calculator adjusts every output based on which species you select.
2 Enter the breeding date. For dogs, use the first breeding if there were several. For livestock, use the date the breeding occurred (live cover or AI).
3 If you have a progesterone-confirmed ovulation date for a dog, enter it. Counting 63 days from ovulation is the most accurate calendar method available for dogs. Without it, the calculator counts 63 days from breeding with a wider window.
4 Use the prep date. Set up the whelping box or birthing area on or before the prep date so the dam has time to settle into it.
5 Begin closer monitoring on the monitoring date. Watch for early labor signs and stay reachable by your vet.

Gestation Length by Species

Dog Gestation (~63 Days)

Canine gestation is 63 days from ovulation, plus or minus a day or two. From a single breeding date, the actual whelping can land anywhere within roughly a 7-day window because sperm can survive for several days in the reproductive tract. A progesterone-confirmed ovulation date tightens the window dramatically. See Progesterone Testing in Dogs for how to get one.

Horse Gestation (~340 Days)

Mares carry foals for an average of 340 days, but normal range runs from about 320 to 365 days. Maiden mares sometimes go later. Foaling almost always happens at night, so plan to have a camera or alarm system in place two to three weeks before the due date.

Goat Gestation (~150 Days)

Does carry kids for roughly 150 days, with a normal range of about 145 to 155 days. Single kids sometimes go a touch longer than multiples. Prepare the kidding pen and watch for ligament softening and udder development in the final week.

Sheep Gestation (~147 Days)

Ewes carry lambs for an average of 147 days, with a normal range of 142 to 152 days. Breed matters here. Hair breeds tend toward the shorter end, larger meat breeds toward the longer end. Have the lambing jugs ready a week early.

Cattle Gestation (~283 Days)

Cows carry calves for an average of 283 days, with a normal range of 279 to 287 days. Heifers sometimes go a few days earlier, and certain breeds (Brahman, for example) tend to run longer. Begin twice-daily checks one to two weeks before the due date.

Why a Calendar Estimate Is Only a Starting Point

Gestation lengths in textbooks are population averages. A given dam, mare, doe, ewe, or cow can deliver anywhere within a normal range that spans days or even weeks. Litter size, breed, individual pattern, and the actual conception date (which is not necessarily the breeding date in dogs) all shift the real due date.

For dogs, the most accurate calendar method available is progesterone testing to confirm ovulation, then counting 63 days forward. For livestock, ultrasound at the appropriate stage confirms pregnancy and helps you anticipate the delivery. The dates this calculator returns are a planning framework. Vet input and actual signs (nesting, udder development, ligament softening, milk drop) are what tell you when delivery is imminent.

For more on the canine side, see Dog Heat Cycle Calculator, the in-tool Heat Cycle Calculator, and Heat Cycle Tracking.

Frequently Asked Questions

How accurate is a whelping date calculator?

For dogs, the answer depends on what date you enter. Counting 63 days from a confirmed breeding date is a textbook estimate that often lands within a few days of the actual whelping. Counting 63 days from a progesterone-confirmed ovulation date is the most accurate calendar method available. Counting from a breeding date without progesterone testing is looser because sperm can live in the reproductive tract for several days, so the actual conception date can be off from the breeding date. Treat the result as a planning window, not a guaranteed day.

Why does the calculator ask for ovulation date for dogs?

In dogs, breeding and ovulation are not the same event. Sperm can survive in the reproductive tract for up to a week, so a single breeding can result in fertilization days later when ovulation finally occurs. Gestation is most accurately measured from ovulation (63 days), not from the breeding act. If you have a progesterone-confirmed ovulation date, use it. If you do not, the calculator falls back to 63 days from the breeding date with a wider window.

How long is gestation for each species?

Dogs average 63 days from ovulation. Horses average 340 days but normal range is 320 to 365. Goats average 150 days (range roughly 145 to 155). Sheep average 147 days (range 142 to 152). Cattle average 283 days (range 279 to 287). Breed, individual animal, litter size, and ovulation timing all affect the actual length, so every result here is a window, not a guarantee.

When should I start preparing the whelping or birthing area?

For dogs, set up the whelping box about a week before the estimated due date so the dam has time to nest. For horses, prepare the foaling stall two to three weeks early because mares often go into labor at night and you want to be ready. For goats, sheep, and cattle, prepare the birthing area one to two weeks before the estimated due date. The dates this calculator returns reflect that recommended prep timing.

When should I begin closer monitoring?

Begin closer monitoring about a week before the estimated due date for dogs, goats, and sheep. For horses, start watching nightly two to three weeks before the due date and consider a foaling alarm or camera. For cattle, begin twice-daily checks one to two weeks before the due date. The "begin closer monitoring" date the calculator returns is calibrated to each species.

Can I save these dates or share them with my vet?

This calculator is anonymous and does not save anything. If you want to keep the dates and track the whole reproductive cycle, BreederHQ records ovulation, breeding, gestation, and whelping or birthing per animal, then refines predictions as you log more events. The free tier covers everything most breeders need.