How the dog pregnancy calculator works
A dog's pregnancy (gestation) lasts an average of 63 days from ovulation, with a normal range of 58 to 68 days from the breeding date. This calculator adds 63 days to the breeding date you enter to give an estimated due date, plus the earliest and latest normal whelping days on either side.
Because sperm can survive several days in the reproductive tract, dating a pregnancy from a single breeding date is always an approximation. For the most precise timing, ask your veterinarian about progesterone testing at the time of mating or an ultrasound around day 28–30.
Week-by-week timeline
- Week 1–3: Fertilization and implantation. Feed a normal adult diet. Avoid live vaccines and non-essential medications.
- Week 4: Ultrasound can confirm pregnancy from about day 28–30. Slowly begin increasing calories.
- Week 5–6: Puppies develop rapidly. Switch to a high-quality puppy or all-life-stages diet.
- Week 7: An X-ray after day 45 can count the number of puppies.
- Week 8: Set up the whelping box in a quiet, warm room. Introduce the mother to it early.
- Week 9: Start monitoring rectal temperature twice daily. A drop below 99°F (37.2°C) means whelping within ~24 hours.
When to call the vet
Contact your veterinarian if the mother is more than 68 days from breeding without labour, if strong contractions last more than 30 minutes without producing a puppy, if more than 2 hours pass between puppies during active labour, or if you see dark green discharge before any puppy is delivered.