Swine Gestation Calculator
Estimate a sow or gilt farrowing date from the breeding date using the common swine gestation rule of about 114 days.
The classic swine gestation estimate used by many pig producers.
Pig Farrowing Date Calculator
Enter the breeding date and choose the gestation estimate. The calculator will show the expected farrowing date, early/late window, and key preparation dates.
Your Swine Gestation Result
This is an estimate only. Actual farrowing can vary, so monitor the sow or gilt closely and consult a veterinarian for health concerns.
Swine Gestation Chart
| Milestone | Approximate Timing | What It Means |
|---|---|---|
| Breeding Date | Day 0 | The date the sow or gilt was bred. |
| Pregnancy Check Window | About 21 days after breeding | Watch for return to heat if pregnancy is uncertain. |
| Mid-Gestation | About day 57 | Halfway point for feeding, body condition, and herd record checks. |
| Prepare Farrowing Supplies | Day 100 onward | Clean area, heat source, bedding, iodine, towels, and piglet care supplies. |
| Move to Farrowing Area | About day 109 | Common planning point before expected farrowing. |
| Expected Farrowing | About day 114 | Average pig gestation estimate. |
What Is a Swine Gestation Calculator?
A swine gestation calculator is a planning tool that estimates when a pregnant sow or gilt may farrow based on the breeding date. Pig producers commonly use the rule of 3 months, 3 weeks, and 3 days, which equals roughly 114 days.
This tool is useful for small farms, homesteads, pork producers, 4-H families, livestock students, and anyone managing breeding records. It helps plan farrowing pen preparation, observation schedules, supplies, and piglet care tasks before the expected due date.
The result should be treated as an estimate, not a guarantee. Individual animals may farrow a little earlier or later depending on age, genetics, litter size, health, nutrition, and management conditions.
How to Use the Pig Gestation Calculator
- Select the date the sow or gilt was bred.
- Choose the gestation length. The default is 114 days.
- Select whether the animal is a sow or gilt for your records.
- Click “Calculate Farrowing Date.”
- Use the early and late window to plan closer observation.
Swine Gestation Length Guide
| Gestation Estimate | Days | Best Use |
|---|---|---|
| Short Estimate | 112 days | Useful when planning an early watch window. |
| Average Estimate | 114 days | Most common farrowing date estimate. |
| Longer Estimate | 115 days | Useful for animals that have historically farrowed later. |
| Late Estimate | 116 days | Planning buffer for extended observation. |
Swine Gestation Calculator FAQs
How long is a pig pregnant?
A pig pregnancy usually lasts about 114 days, often remembered as 3 months, 3 weeks, and 3 days.
What is a pig farrowing date?
The farrowing date is the estimated date when a sow or gilt is expected to give birth to piglets.
Can a sow farrow before 114 days?
Yes. Some sows may farrow a little earlier, so this calculator also shows an early observation window.
Can a sow farrow after 114 days?
Yes. Some pregnancies may run slightly longer. Contact a veterinarian if the animal appears distressed or overdue with concerning symptoms.
Is this calculator useful for gilts?
Yes. It can be used for both sows and gilts, but gilts may need extra observation because it is their first litter.
When should I prepare the farrowing area?
Many producers begin preparing supplies around day 100 and move the animal to a clean farrowing area several days before the expected date.