Gestation & Due-Date Calculator
Enter a mating date and species to see the due-date window and key milestones.
This gestation calculator turns a mating or breeding date plus a species choice into calendar dates. For each species it uses a built-in average gestation length in days and a minimum–maximum range: cat 63–67 (avg 65), dog 58–68 (avg 63), horse 320–362 (avg 340), rabbit 28–33 (avg 31), goat 145–155 (avg 150), sheep 142–152 (avg 147), pig 112–120 (avg 114), and cow 279–287 (avg 283).
Given your date, it adds the average days for the estimated due date and adds the min and max days for the likely window shown below that date. Milestones are separate: each species has a short list of day offsets from the mating date (for example day 21, 28, 42, and 60 for cats); the tool adds those same day counts to your mating date and lists the milestone text beside each calendar date. Dates are formatted in en-AU locale. Individual animals can fall outside the displayed window.
Estimated due date
Wed, 13 Jan 2027
Likely window: Mon, 11 Jan 2027 → Fri, 15 Jan 2027
Average gestation for cat: 65 days (63–67)
Key milestones
- Day 21MonNipples "pink up"; vet can palpate
- Day 28MonUltrasound confirms pregnancy
- Day 42MonX-ray gives accurate kitten count
- Day 60FriSet up the nesting box
Gestation lengths vary by breed and individual. Use this as a planning guide and confirm with your veterinarian.
Preparing for a birth? Read our guides on cat pregnancy and dog whelping.
Gestation calculator FAQ
How is the estimated due date calculated?
You choose a species and enter a mating or breeding date (calendar day). The tool adds that species's average gestation days to the mating date for the headline due date, and adds the species minimum and maximum gestation days for the "likely window" start and end dates.
Which species are included?
The selector includes cat, dog, horse, rabbit, goat, sheep, pig, and cow. Each has fixed average, minimum, and maximum gestation day counts used only for date math on this page.
What are the key milestones?
Milestones are day offsets from your mating date defined per species (for example cat day 21 nipples "pink up", dog day 28 ultrasound, horse day 14 twin check). The calculator adds each offset to your mating date and shows the resulting calendar date with the milestone description.
Can the due window be wrong for my animal?
Yes. The min–max window comes from the fixed species ranges in the tool, not from your individual animal. Gestation length varies by breed and pregnancy; use the output for scheduling and confirm timing with your own records and veterinarian.
Track every pregnancy automatically
AllBreeds counts down to every birth with milestones and reminders across your whole program.
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