🐴 Gestation Due Date Calculator
Enter the breeding date to estimate when your mare is due to foal, based on the average 340-day equine gestation — adjust the length to suit your mare and start planning night checks in good time.
🧮 Estimate the Foaling Date
What is a Gestation Due Date Calculator?
It projects your mare's foaling date from the day she was covered. Because equine pregnancy averages around 340 days, the tool simply adds that span to the breeding date — and lets you enter a different length if your mare tends to run short or long.
Use it to schedule veterinary checks, prepare a clean and safe foaling area, and know roughly when to begin close monitoring. Remember that normal foaling can occur weeks either side of the estimate, so treat it as the middle of a window.
❓ Frequently Asked Questions
How does the gestation due date calculator work?
Enter the breeding or cover date and the tool adds the gestation length — 340 days by default — to project the expected foaling date. You can change the gestation length to match your mare's history or your vet's guidance.
How long are horses pregnant?
Equine gestation averages about 340 days, or roughly 11 months, but a normal range spans from around 320 to 360 days. Mares carrying colts often go slightly longer than those carrying fillies, and individual mares tend to be consistent from one pregnancy to the next.
Why is the due date a window rather than an exact day?
Because normal foaling can happen weeks either side of the 340-day average, the projected date is best treated as the centre of a window. Use it to plan when to start night checks and prepare the foaling area, not as a fixed deadline.
What are the signs that foaling is close?
In the final days you may see udder development and waxing of the teats, relaxation of the muscles around the tail head, and changes in behaviour such as restlessness or seeking isolation. If you're unsure or worried, contact your vet — attended foalings are safest.