Pig Gestation Calculator (Farrowing Date Estimator)
If you’ve bred a sow, one of the most important things to know is when she will farrow (give birth). This pig gestation calculator helps estimate your sow’s due date based on the breeding date.
The average pig gestation period is 114 days, commonly remembered as: “3 months, 3 weeks, and 3 days.”
Enter your breeding date below to estimate your sow’s expected farrowing date and plan ahead for piglet care.
Pig Gestation Calculator
Use the calculator below to estimate when your sow will farrow.
Want to save your results?
FarmKeep lets you record breeding dates, track gestation timelines, and keep all your livestock records organized in one place.
Access calculators, animal records, and farm data anytime from your phone.
Download FarmKeep to get started.
Typical Pregnancy Milestones
After breeding, your sow’s pregnancy will progress through several key stages:
Because gestation length varies only slightly between breeds, most pig farmers simply plan around the 114-day average.
Pig Pregnancy Timeline
Understanding the stages of pig pregnancy can help you manage nutrition, housing, and farrowing preparation.
Early Pregnancy (Days 1–30)
During the first month of pregnancy:
- Fertilized embryos implant into the uterus
- Hormonal changes begin
- The sow typically does not return to heat after 21 days
Physical signs are usually minimal during this stage.
Mid Pregnancy (Days 30–90)
This stage is when fetal growth begins accelerating.
Common developments include:
- Piglets begin forming major organs
- Gradual weight gain in the sow
- Increased nutritional requirements
Farmers often begin adjusting feed rations to support healthy piglet development.
Late Pregnancy (Days 90–114)
The final stage of pregnancy is when farrowing preparation becomes important.
You may notice:
- Enlargement of the sow’s belly
- Mammary gland development
- Nesting behavior
- Increased restlessness
Most farmers move sows to a farrowing pen around day 90–100 to allow time for adjustment before birth.
Signs Your Pig Will Farrow Soon
As the farrowing date approaches, several physical and behavioral changes typically occur.
Common signs of impending farrowing include:
- Nesting behavior (gathering bedding)
- Swollen vulva
- Milk production beginning
- Restlessness or pacing
- Reduced appetite shortly before birth
Most sows will begin farrowing within 24 hours of milk production starting.
Preparing for Pig Farrowing
Proper preparation helps ensure both the sow and piglets stay healthy during birth.
Important steps include:
Prepare the Farrowing Pen
The pen should:
- Be clean and dry
- Have adequate bedding
- Provide protection for piglets from crushing
Monitor the Sow
As the due date approaches:
- Check the sow frequently
- Watch for nesting behavior
- Ensure access to fresh water
Gather Farrowing Supplies
Common supplies include:
- Clean towels
- Iodine for umbilical cords
- Heat lamp for piglets
- Farrowing record sheets
How to Confirm Your Pig Is Pregnant
Before calculating a farrowing date, you’ll want to confirm pregnancy.
The most common ways to confirm pregnancy include:
- Observation of heat cycle: If the sow does not return to heat after 21 days, pregnancy is likely.
- Ultrasound: Often possible around day 25–30.
- Behavioral changes: Appetite and temperament changes may occur.
If you’re unsure whether your sow is pregnant, read our guide on signs of pig pregnancy.
Track Pig Breeding Automatically with FarmKeep
Keeping track of breeding dates, pregnancy timelines, and farrowing records can become complicated quickly.
FarmKeep helps farmers manage livestock records in one place, including:
- breeding records
- gestation tracking
- farrowing logs
- litter records
- animal pedigrees
Instead of calculating due dates manually, FarmKeep automatically tracks your breeding schedule and alerts you when farrowing dates are approaching.
Track your livestock breeding records with FarmKeep →
FAQ
How long are pigs pregnant?
Pigs are typically pregnant for 114 days, which is often remembered as 3 months, 3 weeks, and 3 days.
What is the gestation period for pigs?
Most pigs will farrow between 112 and 116 days after breeding. Larger litters sometimes arrive slightly earlier, while smaller litters may result in pregnancies that extend a few days longer.
Can pigs give birth earlier than 114 days?
Yes. Some pigs may farrow as early as 112 days, especially with larger litters.
Can pig gestation last longer than 114 days?
Some sows may farrow around 115–116 days, particularly if litter size is small.
How many piglets does a sow usually have?
Most pig litters contain 8–14 piglets, though this can vary depending on breed and sow health.
How accurate is a pig gestation calculator?
A pig gestation calculator provides an estimated farrowing date based on average gestation length. While many sows give birth very close to the calculated date, natural variation means farrowing may occur a few days before or after the estimate. Farmers typically begin monitoring closely around day 110 of pregnancy.
How soon can you tell if a pig is pregnant?
The earliest indication of pregnancy is usually when the sow does not return to heat about 21 days after breeding. However, more reliable confirmation methods such as ultrasound scanning can typically detect pregnancy around 25 to 30 days after breeding.
What are the early signs that a pig may be pregnant?
Early pregnancy signs in pigs can include:
- Failure to return to heat after breeding
- Slight behavioral changes
- Increased appetite
- Reduced interest in boars
However, many early signs can be subtle, which is why farmers often rely on heat cycle tracking or ultrasound confirmation.
How many piglets does a sow usually have?
Most pig litters contain 8 to 14 piglets, though this can vary depending on the breed, genetics, age of the sow, and overall health. Some highly productive sows may have litters of 15 piglets or more.
Do all pig breeds have the same gestation length?
Most pig breeds have very similar gestation periods. Common breeds such as Yorkshire, Duroc, Berkshire, Landrace, and Hampshire typically have gestation lengths very close to the average of 114 days.
What should I do if my pig goes past the due date?
If your sow has not farrowed by day 116 or 117, it’s a good idea to monitor her closely. Slight delays are normal, but if the pregnancy extends beyond 118 days, you may want to consult a veterinarian to ensure there are no complications.
