How Long Is a Pig Pregnant? The 3-3-3 Rule Explained
A pig is pregnant for about 114 days, remembered by the 3-3-3 rule: 3 months, 3 weeks and 3 days. The normal range is about 111 to 117 days, and most sows farrow within a couple of days of the calculated date.
What the 3-3-3 rule means
Pig gestation is short and unusually predictable compared with other livestock. Counting from the breeding date: 3 months gets you close, 3 weeks more lands on day 111–112, and 3 more days gets you to about day 114–115. It's a memory trick, not an exact formula, but it puts most people within a day or two of the real date.
Gestation by type
| Type | Typical gestation |
|---|---|
| Commercial breeds (average) | about 114 days |
| Kunekune | about 116 days |
| Pot-bellied pig | about 114 days |
Signs a sow is close to farrowing
- About a week out: move her to a clean, bedded farrowing pen so she can settle in before labor starts.
- Days before: nesting behavior, gathering bedding, and restlessness.
- Close to farrowing: a swollen vulva and milk that can be expressed from the teats, usually meaning farrowing within about 24 hours.
How to work out your sow's farrowing date
Add 114 days to the breeding or insemination date. If the boar ran with her for a few days, add the day he was removed so the window covers every possible farrowing day. The calculator below applies the 3-3-3 rule for you and adds heat-check and farrowing-pen reminders.
Common questions
How many piglets does a sow have?
Commercial sows often have 10–14 piglets a litter. Heritage and Kunekune pigs usually have smaller litters, and first-time gilts have fewer than mature sows.
How soon can a sow be bred again after farrowing?
Sows usually come back into heat 3–7 days after the piglets are weaned, and breeding is normally timed to that heat.
Figures are typical values from university extension and breed-association guidance. Estimates only. Individual animals vary — confirm pregnancy and health questions with your veterinarian.