A horse pregnancy lasts about 340 days from the breeding date, which is 11 months and 10 days (months of 30 days); most births fall between day 320 and day 370. Day 0 is the breeding date, so month 1 is days 0 to 29, month 2 is days 30 to 59, and so on.
How far along is your horse? Pick the breeding date: the calculator shows which day she is on, the days to go and every date on her schedule.
Bred on
Length (days)
340
Average: 340 days. Adjust it for your breed.
Due date
Fri, Feb 4, 2028
Usually Jan 15 – Mar 5, 2028
Milestones
💕
Bred
Day 0 · Mon, Mar 1, 2027
⏳
Halfway
Day 170 · Wed, Aug 18, 2027
🧺
About a week to go: get a clean, quiet birthing area ready
Day 333 · Fri, Jan 28, 2028
🎉
Due date (foaling)
Day 340 · Fri, Feb 4, 2028
Month by month: days and dates
Dates for a horse bred on Mar 1, 2027. Pick your own breeding date in the calculator above.
Day 0 is the breeding date. If she was bred on several days, the calculator counts from the first breeding and the usual window runs to the last breeding + 370 days.
Mares vary more than other farm animals: 320 to 370 days is normal, and many breeders mark 11 months after the last breeding so foals don’t arrive by surprise (Extension Foundation).
Months 2 to 5 (days 30–149)
Nothing on the schedule until day 170 (halfway, month 6). By day 149, 191 days are left to the due date.
Month 6 (days 150–179): halfway
Day 170 (Aug 18, 2027) is halfway through a 340-day pregnancy. From here, 170 days are left to the due date.
Months 7 to 10 (days 180–299)
Nothing on the schedule until day 320 (the usual window opens, month 11). By day 299, 41 days are left to the due date.
Month 11 (days 300–329): the usual window opens
Day 320 (Jan 15, 2028) is the earliest usual date: from here on, a birth is inside the usual range.
Month 12 (days 330–359): a week to go and the due date
Day 333 (Jan 28, 2028) is one week before the due date. The schedule’s reminder for this day: get a clean, quiet birthing area ready.
Day 340 (Feb 4, 2028) is the due date, the average length counted from breeding. It is an estimate; most births fall between day 320 and day 370.
Month 13 (days 360–370): the usual window closes
Day 370 (Mar 5, 2028) is the latest usual date. If that day passes, or anything about the mother worries you, call your veterinarian.
Frequently asked questions
How far along is my horse?
Count the days since the breeding date (the first one, if she was bred more than once). Days 0 to 29 are month 1, days 30 to 59 are month 2, and so on: day 170 is in month 6 and the due date, day 340, is in month 12. The calculator above counts it for you.
How many months is a horse pregnant?
About 340 days, which is 11 months and 10 days. Most births fall between day 320 (month 11) and day 370 (month 13).
When should the birthing area be ready?
The schedule marks day 333 (month 12), one week before the due date: get a clean, quiet birthing area ready. For a horse bred on Mar 1, 2027, that is Jan 28, 2028.
Where the numbers come from
Sources: Extension Foundation (Horses): Management of the Pregnant Mare. Breeds and individual animals differ; change the length in the calculator if yours usually runs early or late. These dates are estimates, not veterinary advice: ask your veterinarian about your animal.