The 340-day reference is approximate; breed, season and individual pregnancies vary.
How to use Mare Gestation Calculator - Horse Gestation
- Read the method and enter quantities in the units shown on the form.
- Check the measurement basis, recorded event, genetic assumptions or the externally supplied care-plan instruction before calculating.
- Select Calculate, then read both the result and its limitations. Reset clears the result and restores the starting form.
Method and scope
Estimated date = entered breeding date + entered reference days. The planning range adds and subtracts your chosen margin.
Work through the input issue
For a related perspective, read Mare Foaling Calendars: A Reference Date Does Not Diagnose Readiness.
Related measurement
Horse Weight Calculator can help with a related question, using its own stated assumptions.
Explore the Animal pregnancy calculators section of Biology calculators.
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