Guinea Pig Pregnancy Calculator
Estimate a guinea pig's due date from the mating date using the published 59–72 day gestation range.
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What this tool does
Estimate a guinea pig's due date from the mating date using the published 59–72 day gestation range. Guinea pig pregnancies are long for a rodent and pups are born fully furred with eyes open. A sow's first litter should ideally be before about 7–8 months of age (pelvic fusion risk) — discuss any guinea pig pregnancy with an exotics vet early, especially a first pregnancy in an older sow.
How to use the Guinea Pig Pregnancy Calculator
- Enter or select mating date (yyyy-mm-dd).
- Read the calculated result; change any measurement to compare alternatives.
Formula
due window = mating date + 59 to 72 days (the published guinea pig gestation range), with 65 days shown as the mid-range estimate; larger litters tend toward the shorter end
- date
- Mating date (YYYY-MM-DD)
Guinea pig pregnancies are long for a rodent and pups are born fully furred with eyes open. A sow's first litter should ideally be before about 7–8 months of age (pelvic fusion risk) — discuss any guinea pig pregnancy with an exotics vet early, especially a first pregnancy in an older sow.
Worked example
For guinea pig pregnancy calculator, the following measurements illustrate the exact method: Mating date (YYYY-MM-DD): 2026-01-01.
Inputs
- Mating date (YYYY-MM-DD)2026-01-01
Result
- Estimated due date (day 65)2026-03-07
- Due window starts (day 59)2026-03-01
- Due window ends (day 72)2026-03-14
Results explained
- Estimated due date (day 65)
- Estimated due date (day 65) from the formula above. Guinea pig pregnancies are long for a rodent and pups are born fully furred with eyes open. A sow's first litter should ideally be before about 7–8 months of age (pelvic fusion risk) — discuss any guinea pig pregnancy with an exotics vet early, especially a first pregnancy in an older sow.
- Due window starts (day 59)
- Due window starts (day 59) from the formula above. Guinea pig pregnancies are long for a rodent and pups are born fully furred with eyes open. A sow's first litter should ideally be before about 7–8 months of age (pelvic fusion risk) — discuss any guinea pig pregnancy with an exotics vet early, especially a first pregnancy in an older sow.
- Due window ends (day 72)
- Due window ends (day 72) from the formula above. Guinea pig pregnancies are long for a rodent and pups are born fully furred with eyes open. A sow's first litter should ideally be before about 7–8 months of age (pelvic fusion risk) — discuss any guinea pig pregnancy with an exotics vet early, especially a first pregnancy in an older sow.
Frequently asked questions
59–72 days — about two months, much longer than rats or hamsters. Pups are born precocial: furred, eyes open, and able to nibble solid food within days, though they nurse for about three weeks.
Bigger litters fill the uterus sooner and tend to arrive toward the 59–63 day end; a single pup may go to 70+ days. The window in this calculator covers both cases.
The pelvic bones separate noticeably (a gap you can feel in front of the genitals) a few days before delivery, alongside nesting behaviour and reduced appetite. A vet or experienced cavy keeper can show you the check.
It can be — pregnancy toxaemia and oversized pups are real risks, and sows first bred after ~7–8 months may be unable to deliver naturally because the pelvic symphysis has fused. Any straining without progress is an emergency.
Before the birth: sows come back into season within hours of delivering, and back-to-back pregnancies are dangerous. House the boar separately from about day 50 onward at the latest.