Dog Pregnancy Due Date Calculator
Calculate your dog pregnancy due date and key milestones.
Enter the first mating date to see the expected whelping timeline.
Dog pregnancy (gestation) lasts a remarkably consistent 63 days from ovulation — or approximately 58–68 days measured from the first mating. The variance depends on when mating occurred relative to ovulation, not on the breed or litter size.
Due date formula:
Whelping Date = Mating Date + 63 days
Because sperm can survive inside a female dog for up to 5–7 days, and eggs remain viable for 2 days after ovulation, the practical window from first mating to birth ranges from 58 to 68 days.
For the most accurate due date: Veterinary progesterone testing pinpoints ovulation directly — the whelping date is then exactly 63 days after confirmed ovulation, with less than 24-hour variance.
Development milestones:
- Day 1–10: Fertilization and travel to uterus
- Day 15–20: Embryo implantation
- Day 22: Heartbeats detectable by ultrasound
- Day 28–35: Ultrasound confirms pregnancy and litter count
- Day 45–50: Skeletal calcification visible on X-ray (X-ray gives most accurate puppy count)
- Day 55+: Nesting behavior begins; temperature drop signals imminent labor
- Day 58–68: Whelping occurs
Temperature drop rule: Within 12–24 hours before labor, the mother’s rectal temperature drops below 99°F (37.2°C) from her normal 101–102.5°F. Monitoring twice daily after day 55 gives advance warning.
Worked example: Mating confirmed on March 10. Add 63 days → Estimated whelp date: May 12 Earliest expected: May 7 (58 days) Latest expected: May 17 (68 days)
Track weight gain (typically 15–25% above pre-pregnancy weight at term) and consult a vet if labor has not begun by day 70.