A healthy dog pregnancy runs about nine weeks, but the maths of exactly when starts with the day she ovulated — which isn't always the day she was mated. This calculator grounds the due-date estimate in the 63-day average and the safe 58–68 day range.
Counting from ovulation, not mating
Sperm can wait for the egg and eggs can be released up to about two days after mating. That's why veterinarians quote ranges: a puppy born on day 60 or day 66 is usually just as healthy as one at day 63. Basing a 'due date' on the 63-day midpoint and a broad window is the most honest framing.
What each week is doing
Embryos implant by week two, fetuses form through weeks three and four, movement starts around week five, and rapid growth plus milk-gland development dominate weeks six through eight. The week tracker here matches the familiar milestones so you can see the pregnancy progressing.
Frequently asked questions
About 63 days from ovulation, with a normal range of 58–68 days from mating. Puppies can be born at the ends of that range and still be perfectly healthy.
Matings rarely coincide with ovulation exactly. Count from the first mating as your earliest reference, but expect the true date to land within the 58–68 day window.
Skeletons calcify enough to count around day 45–49. Palpation later in pregnancy is risky — an X-ray at ~45 days is the safe way to know the litter size.