Animal Gestation Calculator

Pig Gestation Period: How Long Is a Pig Pregnant?

A pig is pregnant for about 114 days, roughly 3 months and 3 weeks. Normal farrowing happens between 112 and 116 days, and a typical litter is 8-12 piglets.

How long is a pig pregnant?

A pig carries her piglet for an average of 114 days, or about 3 months and 3 weeks. Counting from the breeding date, farrowing is normal anywhere from day 112 to day 116.

Key checkpoints across the 114-day pig gestation, measured in days from breeding:

Pig gestation timeline from day 0 to day 114: day 21 Sow returns to heat if she did not hold to service; day 28 Ultrasound scan confirms pregnancy; day 75 Lift the ration: most piglet growth starts now; day 105 Wash the sow, treat for parasites and move her to the farrowing pen; day 112 Nest-building begins; earliest normal farrowing; day 115 Expected farrowing.Day 0Day 114Day 21Sow returns to heat if she did not hold to serviceDay 28Ultrasound scan confirms pregnancyDay 75Lift the ration: most piglet growth starts nowDay 105Wash the sow, treat for parasites and move her to the farrowing penDay 112Nest-building begins; earliest normal farrowingDay 115Expected farrowing
Pig gestation timeline from day 0 to day 114: day 21 Sow returns to heat if she did not hold to service; day 28 Ultrasound scan confirms pregnancy; day 75 Lift the ration: most piglet growth starts now; day 105 Wash the sow, treat for parasites and move her to the farrowing pen; day 112 Nest-building begins; earliest normal farrowing; day 115 Expected farrowing.

Pig gestation stages, month by month

Days 1–28: implantation and confirmation

Embryos implant from about day 13 to 18 and this is when most losses occur. Keep the sow in a stable group, avoid mixing and fighting, and hold feed at a moderate level — overfeeding in early pregnancy reduces embryo survival. Scan at about day 28.

Days 29–74: mid pregnancy

Piglet growth is slow and the sow's requirement barely rises. Feed to body condition, not to appetite; an over-fat sow farrows badly, eats poorly in lactation and has more crushed piglets. This is the right period for vaccinations and any moves.

Days 75–104: rapid piglet growth

Foetal growth takes off and mammary tissue develops. Raise the daily ration, keep water freely available and treat for internal and external parasites before she enters the farrowing house so she does not carry mange or worms to the litter.

Days 105–118: farrowing preparation

Move her into a clean, warm farrowing pen with a creep area at around 30°C for the piglets. Milk can usually be stripped from the teats within 24 hours of farrowing, the vulva swells and she builds a nest. Farrowing itself normally takes two to four hours.

Signs a pig is pregnant

  • No return to heat 21 days after service and no standing for the boar
  • Ultrasound confirmation from about day 28
  • Belly drops and widens from roughly day 75, with visible teat line development
  • Teats become prominent and the udder firms up in the final two weeks

Signs of approaching farrowing

  • Milk can be expressed from the teats within about a day of farrowing
  • Intense nest building, restlessness and chewing at straw 12 to 24 hours before farrowing
  • Contact your vet if labour stalls, if the animal strains without progress, or if there is abnormal discharge before farrowing begins.

What affects pig gestation length

  • Pig gestation is famously easy to remember as three months, three weeks and three days — 115 days — and it is one of the tightest gestations in farm livestock.
  • Larger litters farrow slightly earlier: a sow carrying 16 piglets often farrows a day before a gilt carrying eight served on the same day.
  • Gilts (first-time mothers) tend to farrow around a day earlier than mature sows and produce smaller, lighter litters.
  • Roughly two thirds of piglet weight is laid down in the last three weeks, so the feed increase around day 75 matters far more than anything fed earlier.
  • Sows are the classic nest builders of farm livestock: given straw, a sow will carry and arrange bedding intensely in the 12 to 24 hours before farrowing.

Estimate your pig's farrowing date

Enter the breeding date for an estimated farrowing date at 114 days.

Estimate a pig due date

Estimated farrowing date

Tuesday, 5 January 2027

Earliest

3 Jan 2027

Latest

7 Jan 2027

Open the full Pig gestation calculator

Pig pregnancy FAQs

How long is a pig pregnant?

115 days on average — three months, three weeks and three days. Almost all sows farrow between 112 and 118 days after service, which makes pig due dates unusually easy to plan around.

Does litter size change the farrowing date?

Slightly. Large litters tend to farrow about a day early and small litters a day late, and gilts usually farrow a little earlier than mature sows. The effect is a day or two, not a week.

When should a sow move into the farrowing pen?

About 7 to 10 days before her due date, so around day 105 to 108. Wash her before she goes in, treat for mange and worms, and let her settle before nest building starts so she is not stressed on the day.

How can I tell farrowing is close?

Milk that can be stripped from the teats is the most reliable sign and usually means farrowing within 24 hours. Add a swollen vulva, restlessness, panting and heavy nest building with straw and you are within hours.

How long does farrowing take and when should I intervene?

Two to four hours for a normal litter, with a piglet roughly every 15 to 20 minutes. If she strains hard for more than 30 to 45 minutes with no piglet, or stops with piglets clearly still inside, call your vet — retained piglets kill sows quickly.

More gestation pages

Livestock gestation chart