Sow Gestation Calculator

Free Sow Gestation Calculator — estimate farrowing date, window and weaning date for any sow from the date of service or AI.

915.5K uses Updated · 2026-05-12 Runs locally · zero upload
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How to Use Sow Gestation Calculator

  1. Pick service / AI date — The day of mating.
  2. Read farrowing window — The Sow Gestation Calculator shows the 114-day due date plus 112-/116-day extremes and a suggested weaning date.

Formula & Theory — Sow Gestation Calculator

due_date    = service_date + 114 days
earliest    = service_date + 112 days
latest      = service_date + 116 days
weaning     = due_date + 21 days
elapsed     = today - service_date
remaining   = due_date - today
SymbolMeaning
114Sow average gestation in days
112 / 116Typical range
21Standard weaning age in days

Use Cases for Sow Gestation Calculator

  • Pig farms — Plan farrowing rooms and staff coverage.
  • Veterinary services — Confirm and document due dates.
  • 4-H / Vocational ag. — Teach swine reproduction.
  • Backyard pig keepers — Manage a single litter at home.
  • Genetics & breeding research — Schedule pregnancy checks and DNA sampling.

The Sow Gestation Calculator keeps breeding records tight and farrowing rooms ready.

Frequently asked questions about Sow Gestation Calculator

How long is a sow's pregnancy?

About 114 days — the famous '3 months, 3 weeks, 3 days' rule. Typical range is 112–116 days.

When should I move the sow to the farrowing crate?

Usually 5–7 days before the due date. The Sow Gestation Calculator highlights remaining days so you can plan moves in advance.

When can piglets be weaned?

Most commercial herds wean at 21 days; small farms wean 28–35 days. The calculator suggests a weaning date 21 days after farrowing.

Does breed affect gestation?

Slightly — Yorkshire, Landrace and Duroc all average 114 days; small heritage breeds may be 1–2 days shorter.

Is my data stored?

No, all calculations run locally.