Horse Foaling Calculator
This horse foaling calculator predicts your mare's expected foaling date instantly. Enter the breeding date to calculate the foaling window, then use the guides below to build your foaling kit, set up the foaling stall, and know exactly what to expect — and when to call the vet — through labour and the first hours of the foal's life.
Quick Answer
Horse gestation is 340 days — approximately 48.6 weeks or 11.2 months. Mares foal approximately 340 days after breeding — about 11.2 months — with a wide normal range of 320–370 days. Enter your mare's breeding date in the calculator to calculate the predicted foaling date, then start close foaling watch around day 320 — horses foal extremely fast once labour begins.
Horse (Foaling) Gestation Calculator
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Foaling Kit Checklist
Assemble your foaling kit at least a few weeks before the predicted date — once waxing appears, you may only have hours to prepare.
- Clean towels for drying and stimulating the foal
- Navel dip — dilute iodine or chlorhexidine solution, plus a small dipping cup
- Sterile tail wrap for the mare during delivery
- Foal enema to help pass the first meconium
- Colostrum (frozen from a reliable source, or a colostrum replacer as backup)
- Vitamin E and selenium supplements, as advised by your vet
- Digital thermometer for both mare and foal
- Disposable obstetric gloves
- Flashlight or headlamp — most mares foal at night
- Your veterinarian's emergency number, posted somewhere visible
Setting Up the Foaling Stall
Move the mare into her foaling stall 2–4 weeks before her due date so she has time to settle in and build immunity to the stall's environment — this immunity passes to the foal through her colostrum. The stall should be:
- At least 12x12 feet — large enough for the mare to lie down, stretch out, and deliver safely
- Deeply bedded with clean straw — avoid shavings, which can stick to a wet newborn and irritate its airway
- Thoroughly cleaned and disinfected before the mare moves in
- Well ventilated but free of drafts, kept quiet and low-traffic
- Fitted with good lighting or a foaling camera/alarm so the mare can be monitored without disturbing her — roughly 70% of mares foal between dusk and dawn
Signs Foaling Is Imminent (Final 24–48 Hours)
- Waxing: small beads of dried colostrum appear on the teats, typically 24–48 hours before foaling.
- Udder filling: the udder visibly fills and softens in the days leading up to foaling.
- Tailhead relaxation: the muscles and ligaments around the tailhead and vulva noticeably soften and relax.
- Restlessness: pawing, circling, repeatedly lying down and standing, and looking at the flanks.
- Milk running from the udder in the final 4–6 hours is a strong signal that foaling is close.
The Stages of Labour
- Stage 1 (30 minutes to a few hours): cervical dilation and the foal positioning itself for delivery — the mare shows restlessness, mild colic-like signs, and intermittent sweating.
- Stage 2 (should complete within 30 minutes): active delivery. Horses foal extremely fast once the water breaks — this stage should be complete within 30 minutes. Anything taking significantly longer is an emergency requiring immediate veterinary help.
- Stage 3 (within 3 hours): passage of the placenta. It must pass within 3 hours of delivery — a retained placenta beyond that window is a veterinary emergency that can quickly progress to toxemia and laminitis.
When to Intervene and When to Call the Vet
- Red bag delivery: a red, velvety membrane appears at the vulva instead of the normal white/grey amniotic sac — this means the placenta has separated early and the foal has lost its oxygen supply. Cut the membrane open immediately and call your vet at the same time.
- Dystocia: if you don't see two front feet followed by a nose within a few minutes of active straining, or delivery has not progressed within 20–30 minutes of the water breaking, call your vet immediately — do not wait.
- Retained placenta: not passed within 3 hours of delivery.
- The foal is not standing within 1 hour or nursing within 2 hours of birth.
- The mare shows signs of severe pain, heavy bleeding, or exhaustion at any point during labour.
Immediate Newborn Foal Care
Follow the 1-2-3 rule to track a foal's progress in the first hours of life:
- 1 hour: the foal should be standing on its own.
- 2 hours: the foal should be nursing.
- 3 hours: the foal should pass its first meconium (the dark, sticky first stool) — a foal enema can help if it's straining without success.
Dip the foal's navel in a navel dip within the first hour and again a few hours later to help prevent infection entering through the umbilical stump. Have your vet check the foal's IgG (immunoglobulin) level around 12–24 hours of age to confirm it absorbed enough antibodies from colostrum — failure of passive transfer is a leading cause of neonatal illness and is easily corrected if caught early.
Common Foaling Complications
- Dystocia: a difficult or obstructed delivery, often caused by an abnormal foal position or presentation — requires prompt veterinary assistance.
- Red bag delivery: premature placental separation, cutting off the foal's oxygen before it is born — a time-critical emergency.
- Retained placenta: the placenta is not passed within 3 hours, raising the risk of toxemia and laminitis.
- Foal rejection: the mare, especially a maiden mare, refuses to let the foal nurse or shows aggression toward it — needs careful, often vet-guided, management.
Post-Foaling Care for the Mare
- Foal heat: most mares cycle back into heat around 7–10 days after foaling. It's biologically possible to rebreed on this heat, but many vets and breeders prefer to wait for the next cycle to give the uterus more time to fully involute.
- Uterine involution: the uterus shrinks back toward its pre-pregnancy size and condition over the weeks following foaling — your vet can check its progress at a post-foaling exam.
- Nutrition: a lactating mare has significantly higher energy and protein needs than a pregnant mare — work with your vet or an equine nutritionist to adjust her feed accordingly.
- Rebreeding decision: weigh the mare's body condition, uterine health, and the foal heat's lower conception rates against the benefit of keeping her on an annual foaling schedule.
Want the Full Pregnancy Timeline?
This calculator focuses on foaling — the birth event itself. For a complete week-by-week pregnancy timeline, nutrition guidance, and vet visit schedule from breeding through foaling, see our full horse gestation calculator.
Frequently Asked Questions
How do I predict my mare's foaling date?
Add 340 days to the breeding date, with a normal range of 320–370 days — one of the widest windows of any common domestic animal. Use the calculator above for an exact predicted date, then begin close foaling watch around day 320.
What should be in a foaling kit?
A foaling kit should include clean towels, a navel dip (dilute iodine or chlorhexidine), a sterile tail wrap for the mare, a foal enema, colostrum (frozen or a colostrum replacer as backup), vitamin E and selenium supplements, a digital thermometer, disposable gloves, a flashlight or headlamp, and your veterinarian's emergency number posted where you can see it — most mares foal at night.
How do I set up a foaling stall?
A foaling stall should be at least 12x12 feet, deeply bedded with straw (shavings can stick to a wet newborn and irritate the airway), thoroughly cleaned and disinfected, well ventilated but draft-free, and fitted with good lighting or a foaling camera so the mare can be monitored without disturbing her. Move the mare in 2–4 weeks before her due date so she builds immunity to the stall's specific environment and passes that immunity on through her colostrum.
What are the signs that foaling is imminent?
In the final 24–48 hours, watch for waxing (small beads of dried colostrum on the teats), a filling and softening udder, relaxation of the muscles around the tailhead and vulva, and restlessness — pawing, circling, repeatedly lying down and standing, and looking at the flanks. Milk running from the udder in the last 4–6 hours is a strong signal that foaling is close.
What are the stages of labour in a mare?
Stage 1 (30 minutes to a few hours) is cervical dilation and positioning of the foal, marked by restlessness and mild colic-like signs. Stage 2 is active delivery and is extremely fast in horses — it should be complete within 30 minutes of the water breaking; anything much longer needs immediate veterinary help. Stage 3 is passage of the placenta, which must happen within 3 hours — a retained placenta beyond that window is a veterinary emergency.
What is a red bag delivery and why is it an emergency?
A red bag delivery happens when the placenta separates from the uterus before the foal is born, so a red, velvety membrane appears at the vulva instead of the normal white/grey amniotic sac. It means the foal has lost its oxygen supply. This requires immediately cutting the red membrane open and delivering the foal as fast as possible, followed by an emergency call to your vet — every minute of delay increases the risk of the foal being born compromised.
How soon should a foal stand, nurse, and pass meconium?
Follow the 1-2-3 rule: a healthy foal should stand within 1 hour of birth, nurse within 2 hours, and pass its first meconium (dark, sticky first stool) within 3 hours. Missing any of these milestones warrants a call to your vet — delayed standing, nursing, or defecation can signal prematurity, weakness, or a blocked bowel.
What are the most common foaling complications?
The most common complications are dystocia (a difficult or obstructed delivery, often from an abnormal foal position), red bag delivery (premature placental separation), retained placenta (not passed within 3 hours, risking toxemia and laminitis), and foal rejection, where the mare — especially a maiden mare — refuses to let the foal nurse or shows aggression toward it.
When does a mare come back into heat after foaling?
Most mares experience 'foal heat' around 7–10 days after foaling. While it's biologically possible to rebreed on this heat, many breeders and vets prefer to wait for the following cycle, since the uterus may not have fully involuted (returned to its pre-pregnancy state) yet, which can lower conception rates and raise early pregnancy loss risk.
Sources & References
- Merck Veterinary Manual — Parturition and dystocia in the mare
- American Association of Equine Practitioners (AAEP) — Foaling and neonatal foal care
- Penn State Extension — Equine reproduction and foaling management
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Kanika
Researched and reviewed by Kanika, founder of GestationCalc. All gestation data is verified against primary veterinary and agricultural sources before publication.
Last reviewed: September 8, 2026