Horse Pregnancy Calculator

🐎 Horse Pregnancy Calculator

Calculate your mare’s foal due date and track pregnancy milestones. Average equine gestation is 340 days (11 months).

Date of Last Breeding / Conception Mare Breed

Expected Foal Due Date

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Early Pregnancy Check

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Day 14–16 ultrasound

Heartbeat Detected

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Around day 24–26

2nd Trimester Starts

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Day 114 (Month 4)

3rd Trimester Starts

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Day 226 (Month 8)

Udder Development

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~Day 310 (2–4 wks before)

Waxing of Teats

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~24–48 hours before foaling

⚠️ Normal range is 320–370 days. Foals born before 320 days are premature. Always have a vet available in the final 2–4 weeks. Monitor for signs of imminent foaling: waxing teats, relaxed muscles around tailhead, and restlessness.

Horse Gestation Period — What to Expect

The average horse pregnancy lasts approximately 340 days (around 11 months), though normal gestation ranges from 320 to 370 days. Draft breeds tend to carry slightly longer (avg 345 days) while ponies often foal a little earlier (avg 330 days). Mares bred in the spring tend to have shorter gestations than those bred in autumn.

Signs a Mare Is About to Foal

2–4 weeks before: Udder (mammary glands) begin to enlarge and fill with milk. 1–2 weeks before: Muscles relax around the tailhead and hindquarters. 24–48 hours before: Waxing — a yellow, waxy secretion appears on teat ends. Hours before: Mare becomes restless, paces, lies down and gets up repeatedly, sweats, and shows signs of mild colic.

Horse Pregnancy FAQ

How long is a horse pregnant? On average, 340 days (11 months 5 days), with a normal range of 320–370 days.

How early can you detect horse pregnancy? Ultrasound can detect a pregnancy as early as day 14–16. Blood tests (eCG/PMSG) can confirm pregnancy from day 40–120.

How many foals can a mare have in a year? Typically one. Mares have a 11-month gestation so most have one foal per year. Twins are rare and high-risk in horses.

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