Guinea Pig Gestation Calculator
This guinea pig gestation calculator finds the expected due date instantly. Enter the breeding date to calculate the gestation period for your sow, view key milestones, and plan for the litter's arrival. Covers all common guinea pig breeds.
Quick Answer
The gestation period for a guinea pig averages 65 days (approximately 9.3 weeks), with a normal range of 59–72 days. Larger litters tend to be born earlier in the range. Enter your sow's breeding date above to calculate the exact expected due date and key milestones.
Guinea Pig Gestation Calculator
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How to Use This Calculator
Enter the date your sow was bred using the date picker. Select the breed from the dropdown for a slightly more precise estimate — Peruvian and Silkie sows tend to carry a few days longer than American or Teddy sows. Click Calculate Due Date to see the expected due date, earliest and latest dates in the normal range, and a full milestone timeline.
Because guinea pig pregnancy carries real risk for sows bred after 6–7 months of age, confirm the breeding date as precisely as you can and monitor closely from day 59 onward. Results are saved in your browser between visits.
How Long Is a Guinea Pig Pregnant?
The gestation period for a guinea pig averages 65 days — approximately 9.3 weeks. This is unusually long for a small rodent: guinea pig pups are precocial, born fully furred, eyes open, with teeth, and able to walk and eat solid food within hours of birth. That advanced development requires more time in the womb than altricial species like mice or hamsters, whose pups are born blind and hairless.
Early pregnancy (days 1–25): Embryo implantation occurs around day 14. There are no outward signs of pregnancy during this window. A veterinarian can sometimes detect a heartbeat by ultrasound around day 20. Avoid unnecessary handling or stress during this critical period.
Mid-pregnancy (days 25–45): Pups develop fur and grow steadily. The sow's appetite increases and her weight climbs noticeably. This is a good time to gradually increase her intake of vitamin C-rich vegetables, since guinea pigs cannot synthesize their own vitamin C and pregnant sows need more of it.
Late pregnancy (days 45–65): The abdomen becomes visibly wide and pear-shaped. The pelvic bones on either side of the spine widen and become easy to feel — a normal and necessary preparation for delivery. Labor is typically quick, often completing within 30 minutes to a few hours, and pups are up and moving almost immediately after birth.
Guinea Pig Gestation Period in Days, Weeks and Months
The table below converts the guinea pig gestation period into days, weeks, and months for easy reference.
| Measurement | Average | Normal Range |
|---|---|---|
| Days | 65 days | 59–72 days |
| Weeks | 9.3 weeks | 8.4–10.3 weeks |
| Months | 2.1 months | 1.9–2.4 months |
Gestation Period by Guinea Pig Breed
| Breed | Avg. Gestation (Days) | Notes |
|---|---|---|
| American | 65 days | Most common short-haired breed |
| Abyssinian | 65 days | Rosetted coat; average gestation |
| Peruvian | 68 days | Long-haired; tends toward longer end |
| Silkie (Sheltie) | 68 days | Long-haired; tends toward longer end |
| Teddy | 64 days | Dense, wiry coat; slightly shorter |
| Skinny Pig (hairless) | 63 days | Hairless breed; shortest average |
| Coronet | 67 days | Rosetted coat; average gestation |
How We Calculate Guinea Pig Gestation
The guinea pig gestation calculator uses the formula: Due Date = Breeding Date + 65 days. The 65-day average is derived from published small-animal veterinary research and validated by the Merck Veterinary Manual. Because litter size significantly affects gestation length in guinea pigs, the calculator shows the full 59–72 day range so you can plan for early or late delivery.
Frequently Asked Questions
Sources & References
- Merck Veterinary Manual — Guinea pig (cavy) reproduction
- USDA National Agricultural Library — Companion animal care and welfare resources
- Cornell University College of Veterinary Medicine — Small mammal reproduction
- Penn State Extension — Small animal husbandry reference
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GestationCalc Editorial Team
Our editorial team includes animal husbandry specialists, veterinary consultants, and agricultural extension educators. Content is reviewed against peer-reviewed research and guidance from USDA, Penn State Extension, and the Merck Veterinary Manual.
Last reviewed: August 26, 2026