Swine Gestation Calculator
Enter the breeding date to estimate when a sow is due to farrow. The default uses the commonly cited swine gestation of 114 days (the '3 months, 3 weeks, 3 days' rule of thumb) and shows the typical range. Treat this as a planning estimate, not a guarantee.
Last updated: September 25, 2026
Frequently asked questions
How long are pigs pregnant?
About 114 days on average, commonly remembered with the mnemonic '3 months, 3 weeks, 3 days.' Farrowing is typically reported between roughly 110 and 118 days after breeding.
Is the '3 months, 3 weeks, 3 days' rule exact?
It's a widely used memory aid that works out to about 114 days, close to the typical average, but actual farrowing still varies within the normal range for the reasons any biological process does.
Does litter size affect farrowing timing?
Some variation is associated with litter size and the individual sow, though the effect is generally smaller than the natural range of individual variation.
How is this different from the Sheep or Goat Gestation Calculators?
Swine gestation, at about 114 days, is notably shorter than sheep (about 147 days) or goats (about 150 days), so this tool uses its own species-appropriate default and range.
When should farrowing accommodations be ready?
Many pork producers prepare farrowing areas several days before the estimated date, since exact timing within the normal window cannot be predicted precisely.
When should I involve a veterinarian?
If you have concerns about the pregnancy, if farrowing doesn't occur within a reasonable window past the estimate, or if the sow shows signs of distress, contact a veterinarian experienced with swine.