Pig Gestation Calculator

Pig pregnancy averages 114 days, about 3 months, 3 weeks and 3 days, in this calculator. Enter the breeding date to estimate farrowing.

Pig gestation at a glance

Average used by this calculator	114 days (about 3.7 months)
Window shown by this calculator	112 to 118 days after breeding
Due date formula	Breeding date + 114 days
Birth is called	Farrowing
Mother	Sow (gilt for a first litter)
Young	Piglets

The farrowing date is a planning estimate. Sows may farrow before or after day 114; Merck gives 115 to 116 days as a modern average from first service, while Penn State says most sows farrow between days 110 and 117.

Signs farrowing is near

Some farrowing signs appear only shortly before the first piglet.

Abdomen swells
Mammary glands swell
Swaybacked appearance
Vulva relaxes
Restlessness
Nest building
Mammary glands become firm
Frequent urination
Frequent defecation
Faster breathing

Pig pregnancy timeline

Days 18 to 24	A return to heat can be checked after service.
Days 26 to 30	Real-time ultrasound pregnancy checks are commonly done.
After day 55 in gilts	External pregnancy signs may become visible.
After day 84 in sows	External pregnancy signs may become visible.

Frequently asked questions

How long is a pig pregnant?

The pig calculator uses 114 days after breeding, the traditional 3 months, 3 weeks and 3 days estimate for farrowing.

How do I calculate a pig farrowing date?

Enter the breeding date and the pig calculator adds 114 days for an estimated farrowing date and shows its planning window.

What signs show farrowing is near?

A sow may become restless, build a nest, show swollen mammary glands and breathe more quickly before farrowing.

When should I call a veterinarian during farrowing?

Purdue says intervention is warranted if a sow labors for more than 30 to 45 minutes without a piglet. If no personnel experienced in delivering piglets is available, contact your veterinarian immediately.