Horses • pregnancyVerified Scientific Formula
Horse Pregnancy & Foaling Due Date Calculator
Computes estimated foaling due date, trimester milestones, and pre-foaling vaccination deadlines for pregnant mares.
Enter Parameters
Calculated Output
Estimated Time to Foaling Due Date
160Days Remaining53% Completed
What This Result Means
On Day 180 of ~340 (First Half of Gestation).
Calculation Details & Practical Equivalents
Gestation Progress
53%
Current Stage
First Half of Gestation
Normal Foaling Window
Days 320 – 365
Formula & Mathematical Methodology
Standard Mathematical Formula
Equine Gestation = 340 Days Average from Ovulation (Normal Range: 320 to 365 days)
Formula Variables Defined
DaysDays Since Breeding(days)
Elapsed days
Step-by-Step Calculation Example
Example: 340-Day Equine Gestation
- 340 days - 180 days = 160 days remaining until estimated foaling
Final Output: Day 180 of 340 — Mid-Gestation (160 Days Remaining)
Key Assumptions
- Single foal gestation.
Biological Limitations
- Mares have broad normal gestation variation (320-365 days).
Verified Scientific & Veterinary Sources
Version: 1.0•Methodology Reviewed: 2026-01-22
1. The Merck Veterinary Manual (11th Edition)textbook
Aiello, S.E. and Moses, M.A. (Eds.) (2020). Merck & Co., Inc., Kenilworth, NJ
Access Source Authority Horse Pregnancy & Foaling Due Date Calculator — FAQs
Average equine gestation is 340 days (roughly 11 months and 10 days).
Related Calculators & Tools
All Horses CalculatorsHorses
Horse Weight Calculator (Heart Girth & Length)
Calculates horse body weight in pounds or kilograms from heart girth and body length measurements.
Calculate
Horses
Horse Digestible Energy (DE / Calorie) Calculator
Computes daily digestible energy requirements in Megacalories (Mcal/day) for horses across all workloads from maintenance to heavy work.
Calculate