Pig Gestation Calculator

Enter a sow or gilt's breeding date to get her farrowing date, the day to move her into the farrowing crate, and when her next litter could come.

You typeWe calculate

How it's calculated

Farrowing date = breeding date + 114 days
Normal range = day 113 to day 117
Into the crate = farrowing date - 4 days
Next heat = weaning + 3 to 7 days

Dates are counted in whole calendar days, so leap years and daylight saving time never shift a due date.

Sources and worked example

Expected farrowing dateFeb 6, 2027Normal range Feb 5 to Feb 9, 2027 · 114-day gestation

114-day gestation timeline (3 months, 3 weeks, 3 days):Bred Oct 15, 2026 → Ultrasound check Nov 10 to Nov 14, 2026 → Into farrowing crate Feb 2, 2027 → Farrowing window Feb 5 to Feb 9, 2027.

1. Sow farrowing milestones

Milestones for this sow
Milestone	Date
Watch for a return to heat (days 18 to 24)	Nov 2 to Nov 8, 2026
Ultrasound pregnancy check (days 26 to 30)	Nov 10 to Nov 14, 2026
Treat for internal and external parasites (days 86 to 93)	Jan 9 to Jan 16, 2027
Repeat parasite control (day 107)	Sat, Jan 30, 2027
Wash her and move her into the farrowing crate or pen (day 110)	Tue, Feb 2, 2027
Start of typical farrowing range (day 113)	Fri, Feb 5, 2027
Expected farrowing date (day 114)	Sat, Feb 6, 2027
End of typical farrowing range (day 117)	Tue, Feb 9, 2027
Wean the litter at 4 weeks (day 142)	Sat, Mar 6, 2027
Back in heat: breed the first week after weaning (days 145 to 149)	Mar 9 to Mar 13, 2027

2. Farrowing crate & next litter

Ultrasound pregnancy checkNov 10 to Nov 14, 2026

Wash and move to farrowing crateFeb 2, 2027

Next litter, if rebred after weaning at 4 weeksJul 1 to Jul 5, 2027

Weaning and next litter schedule
Next-litter step	Date
Wash & move to crate (4 days out)	Feb 2, 2027
Expected farrowing date	Feb 6, 2027
Wean piglets at 4 weeks	Mar 6, 2027
Return to heat (3 to 7 days after weaning)	Mar 9 to Mar 13, 2027
Next litter due (if rebred on first heat)	Jul 1 to Jul 5, 2027

Farrowing more than one sow?This page works out one breeding date at a time. In the Livestock Tracker Spreadsheet, every sow's breeding date automatically fills in her expected farrowing date and countdown alongside piglets born and surviving, vaccine and withdrawal dates, daily weight gain and profit.

Tracking a herd of sows or gilts this year?

An estimate for planning, not veterinary advice. Work with your vet on pregnancy checks, vaccines and farrowing.

The full template

Track every sow's breeding, farrowing and litter in one herd file

Breeding & Birthing: enter the breeding date and species, and the farrowing date and countdown fill in
Pigs born and pigs surviving logged with every litter
Health Log with next-due flags for vaccines and dewormers, and withdrawal days for a safe-to-sell date
Weight Log with average daily gain, plus feed costs and sales for profit by species

Livestock Tracker Spreadsheet$17.99One-time · instant downloadExcel + Google Sheets + PDF guide5.0 shop rating on Etsy

How the pig gestation calculator works

A sow's farrowing date is her breeding date plus the length of her pregnancy. Purdue's College of Veterinary Medicine gives 114 days, the old rule of 3 months, 3 weeks and 3 days, so 114 is the default. NADIS calls 113 to 117 days quite normal, and the calculator shows that range.

1. Enter the breeding date

Use the day she was bred or inseminated. If she was bred on two days in the same heat, use the first. Gilts and sows use the same gestation length.

2. Plan the milestones

Day 18 to 24: a sow's heat cycle is 21 days, with a range of 18 to 24 (Merck). Watch for her to come back into heat. If she does, she did not settle.
Day 26 to 30: Merck says B-mode ultrasound is generally used now to confirm pregnancy. Purdue says a vet can tell at about 30 days.
3 to 4 weeks out: treat for internal and external parasites (Missouri and NDSU), and repeat one week before farrowing (Missouri). Ask your vet which vaccines to give before farrowing.
4 days out: wash her and move her into the farrowing crate or pen (Missouri). Set up a heat source for the piglets.
The last day or two: the udder fills with colostrum 24 to 48 hours before farrowing (Purdue).

3. Plan the next litter

The calculator assumes weaning at 4 weeks, the youngest weaning age NDSU recommends. Merck says most sows come into heat 3 to 7 days after weaning, and Missouri says to breed in that first week. Add another gestation and you have the window for her next litter.

Worked example

A sow is bred on Thu, Oct 15, 2026. 114 days later is Sat, Feb 6, 2027. The normal range runs Feb 5 to Feb 9, 2027. She should be washed and in the farrowing crate by Tue, Feb 2, 2027.

Worked example milestones
Watch for a return to heat	Nov 2 to Nov 8, 2026
Ultrasound pregnancy check	Nov 10 to Nov 14, 2026
Treat for internal and external parasites	Jan 9 to Jan 16, 2027
Repeat parasite control	Jan 30, 2027
Wash her and move her into the farrowing crate or pen	Feb 2, 2027
Start of typical farrowing range	Feb 5, 2027
Expected farrowing date	Feb 6, 2027
End of typical farrowing range	Feb 9, 2027
Wean the litter at 4 weeks	Mar 6, 2027
Back in heat: breed the first week after weaning	Mar 9 to Mar 13, 2027

Weaned at 4 weeks on Mar 6, 2027, she should come into heat Mar 9 to Mar 13, 2027. Bred then, her next litter is due Jul 1 to Jul 5, 2027.

Where the sources differ

Purdue gives 114 days. NADIS gives 115 as typical, and Merck says gestation has been getting longer and now runs 115 to 116 days, give or take one, from first service. If your sows tend to farrow a day or two after the date here, type 115 or 116.

Advice on when to move her differs more. Missouri says four days before farrowing and NDSU about three. UK guidance from NADIS says five to seven days. Follow your vet and any rules that apply to your farm.

Sources

FAQ

Common questions

How long is a pig pregnant?

About 114 days: 3 months, 3 weeks and 3 days. The UK pig health service NADIS calls 113 to 117 days quite normal, and Merck notes the average in modern herds has crept up to 115 or 116 days.

How do I calculate a farrowing date?

Add 114 days to the breeding date. A sow bred on October 15 is due February 6. If she was bred on two days in one heat, count from the first.

When should a sow go into the farrowing crate?

University of Missouri Extension says to wash her and move her in four days before farrowing. North Dakota State says about three days.

How soon can I tell if a sow is pregnant?

A vet can check with ultrasound from about 26 to 30 days after breeding. Watch for her to come back into heat 18 to 24 days after breeding; a sow that cycles again did not settle.

When can a sow be bred again after farrowing?

Most sows come into heat 3 to 7 days after the piglets are weaned, and Missouri suggests breeding in that first week. Weaning at 4 weeks puts her next litter about five months after this one.

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