Mare Gestation Calculator
Excited for your foal’s arrival? Use this easy calculator to estimate your mare’s foaling day and keep track of her pregnancy.
A mare (female horse) is pregnant for around 338 days—that’s just a bit over 11 months. While 338 days is the average, pregnancies can range from 330 to 345 days. Larger horses may carry a little longer, and smaller ponies often a bit shorter. Most mares have only one foal per pregnancy.
How to Use the Mare Gestation Calculator
It’s super simple: just enter the date your mare was bred (the day she successfully mated). You’ll get:
- Her estimated foaling date and a full date range,
- The day of her pregnancy she’s currently on, and
- The day of the week her labor might happen.
Keep in mind, every mare is unique, so she may foal a little before or after the estimated date.
How to Calculate the Foaling Date Yourself
To calculate foaling manually, here’s the formula:
Foaling Date = Mating Date + 338 Days (the average pregnancy length)
For the range of possible foaling days:
– Earliest = Mating Date + 331 Days
– Latest = Mating Date + 346 Days
Want to Know How Far Along Your Mare Is?
If you know the date your mare was bred, here’s how to check how far along she is:
Pregnancy Day = Current Date – Mating Date
It’s a simple way to see how close she’s getting to her foaling day, and our calculator does this too!
What to Expect During Horse Pregnancy
Horses are “long-day breeders,” meaning they’re most fertile during spring and summer (May to August), when daylight is longest.
Each heat cycle lasts about 21 days, but in peak summer, it can shorten to 18 days. Your mare will only be “on heat” and ready to mate for about 4-5 days. Ovulation happens about 24 hours before the end of her cycle, which is the best time to breed.
If she conceives, her pregnancy will last around 338 days. If not, she’ll start another cycle. A vet can confirm pregnancy with an ultrasound as early as 15 days after mating, with another check at 45 days.
Caring for Your Pregnant Mare
Here are some simple steps to keep your mare healthy during pregnancy:
- Regular Vet Checks: Help track her health and spot any early issues.
- Good Nutrition: Make sure she’s getting the right food; her needs will increase closer to foaling.
- Light Exercise: Some movement is good, but keep it gentle as she nears her due date.
- Foaling Area: Prepare a clean, quiet space for her to give birth.
Signs Your Mare Is Close to Foaling
Here are a few signs she might be ready to foal soon:
- Udder Changes: Her udder will swell and might produce a waxy fluid.
- Restlessness: She may paw at the ground or seem unsettled.
- Temperature Drop: Her body temperature could drop slightly before labor.
Labor can take anywhere from one to several hours, so have supplies like towels and gloves ready.