Horse Gestation Calculator
A horse's gestation period is about 340 days, or roughly 11 months, though it ranges from 320 to 370 days depending on breed and individual animal.
How to use the horse gestation calculator
- 1. Choose what you know. Enter the breeding date to get a due date, or switch to the target due date mode to work backwards to the breeding date you need.
- 2. Refine the inputs. The calculator uses the 340-day average for this species.
- 3. Plan around the range. Use the earliest and latest dates and the milestone timeline to schedule checks, feed changes and preparation of the foaling area.
Calculate a foal due date
Estimated foaling date
Sunday, 4 July 2027
Earliest
14 Jun 2027
Latest
3 Aug 2027
0 of 340 days elapsed
Milestone timeline
| Day | Milestone | Date |
|---|---|---|
| 16 | Ultrasound to check for twins | 14 Aug 2026 |
| 300 | Increase feed, begin foaling prep | 25 May 2027 |
| 320 | Move to foaling stall, remove Caslick if present | 14 Jun 2027 |
| 340 | Expected foaling | 4 Jul 2027 |
How long is a horse's gestation period?
The average is 340 days from breeding to foaling, about 11 months. Anything between 320 and 370 days is normal, and a typical litter is 1 foal. Treat the calculated date as the middle of that window rather than a fixed appointment.
Horse gestation table: breeding date to foaling date
Breeding dates one week apart with the matching foaling date at 340 days.
| Breeding date | Expected foaling date |
|---|---|
| 29 Jul 2026 | 4 Jul 2027 |
| 5 Aug 2026 | 11 Jul 2027 |
| 12 Aug 2026 | 18 Jul 2027 |
| 19 Aug 2026 | 25 Jul 2027 |
| 26 Aug 2026 | 1 Aug 2027 |
| 2 Sept 2026 | 8 Aug 2027 |
| 9 Sept 2026 | 15 Aug 2027 |
| 16 Sept 2026 | 22 Aug 2027 |
| 23 Sept 2026 | 29 Aug 2027 |
| 30 Sept 2026 | 5 Sept 2027 |
| 7 Oct 2026 | 12 Sept 2027 |
| 14 Oct 2026 | 19 Sept 2027 |
Working backwards from a target foaling date
If you want foals on the ground in a particular week, switch the calculator to target date mode and enter the date you are aiming for. It subtracts 340 days to give the breeding date to book, plus the earliest and latest service dates that still land inside your window.