Mare Gestation Calculator
Determine the expected foaling date for pregnant horses (mares) using breeding or insemination dates.
Pregnancy Parameters
Enter the start date of gestation.
Estimated Foaling Date
KEY MILESTONES
Expert Tip
Equine gestation averages 340 days, but ranges significantly from 320 to 370 days. Keep close contact with your equine veterinarian during the final weeks.
Calculation Methodology & Details
Gestation Formula
Equine gestation is calculated by adding 340 days to the last ovulation or mating date. The normal gestation range is 320 to 370 days.
Clinical Considerations
Gestation durations can vary based on animal breed, age, litter size, and genetic factors. If you observe signs of distress or if delivery departs significantly from the calculated date, consult a veterinarian immediately.
How to Calculate Horse Due Date: Step-Step
Estimate the mare's delivery date with these steps:
Note the Ovulation/Breeding Date
Record the date of artificial insemination or stallion service.
Add Gestation Days
Add 340 days to estimate the expected foaling date.
Prepare for Birth Window
Allow a broad window between day 320 and 370 for normal delivery.