Guinea Pig pregnancy guide
How long is a guinea pig pregnant?
A guinea pig is pregnant for about 65 days (about 9 weeks). The normal range is 59 to 72 days, so most pups arrive within that window rather than on the exact average day.
Quick rule: Count 9 weeks forward from the mating date. The birth window runs from day 59 to day 72.
How to use the guinea pig pregnancy calculator
1. Enter the mating date. The day she was put with the boar. Tap Use today if it was today.
Then follow the schedule. Each task gets a real date, the next one is highlighted, the status shows whether your sow is on track, and the week by week cards above show where things stand. Use Copy schedule or Add to Google Calendar to keep it.
Gestation formulas
- Estimated birth date = mating date + 65 days
- Earliest normal birth = mating date + 59 days
- Latest normal birth = mating date + 72 days
- Breed adjustment = breed average minus 65 days, applied to the whole window
- Call your vet if nothing has happened by day 72
Care schedule for a pregnant sow
| When | Task | Why |
|---|---|---|
| Day 21 | Track her weight | Weigh her twice a week. Steady gain is normal. Sudden loss needs a vet. |
| Day 30 | Extra vitamin C and hay | Pregnant sows need more vitamin C, fresh greens, and unlimited hay. |
| Day 56 | Vet pelvic check | Your vet can check that the pelvic gap is widening before birth. |
Signs of birth and when to call the vet
Labour is close if she has
- ✓Pelvic gap widens to a finger width
- ✓Less active, sitting hunched
- ✓Squeaking or straining
- ✓Discharge or blood
Call your vet immediately if
- !Strong straining for 30 minutes with no pup born
- !A baby is visible but stuck, or comes backwards with no progress
- !Heavy bleeding or foul-smelling discharge
- !She is weak, collapsed, off her food or in obvious pain
- !No birth by day 72
Frequently asked questions
How long is a guinea pig pregnant?
A guinea pig is pregnant for about 65 days (about 9 weeks). Most pups arrive between day 59 and day 72.
How accurate is this calculator?
It uses the average length and the normal range published in veterinary references, adjusted for the breed you pick. Individual animals vary, so treat the date as the middle of a window, not a promise.
What if she goes past the due date?
Going a few days past the average is normal. The calculator marks day 72 as the end of the usual window and day 72 as the point to call your vet even if she seems well.
What are the signs that birth is close?
Pelvic gap widens to a finger width. Less active, sitting hunched. Squeaking or straining.
Is my data saved?
No. Everything is calculated in your browser. Nothing you type is stored or sent anywhere.
Disclaimer: This calculator gives estimates for planning only. It is not veterinary advice and cannot replace an examination by your vet. If you are worried at any stage, especially around birth, contact your vet promptly.
