Dog Pregnancy Calculator — Whelping Due Date
Canine gestation averages 63 days from ovulation. Enter the mating date and get the expected whelping due date, the earliest and latest safe delivery window, and all key development milestones — ultrasound, x-ray, and whelping box dates.
If multiple matings occurred, use the first date.
4 Sept 2026 (day 63)
- 1
Canine gestation period
63Average 63 days from mating date to whelping. - 2
Days elapsed since mating
10 - 3
Days until due date
63 − 10 = 53
How does this calculator work?
Add 63 days to the mating date for the average due date. Safe whelping window is days 58–65. Key milestones: ultrasound at day 25–28, x-ray puppy count at day 45, whelping box at day 55. Call your vet if no birth by day 65. Formula: due date = mating + 63 days.
Formula
How this is calculated
The canine gestation period is 63 days counted from ovulation — but because ovulation is not directly observed in most cases, the convention is to count from the first mating date, giving a range of 58–68 days from that date for normal whelping. The average used here is 63 days (approximately 9 weeks).
Key landmarks during pregnancy: embryos implant in the uterine lining around days 7–10. By day 25–28 a vet can detect heartbeats via ultrasound, and by day 35 fetal movement is visible. Skeletal calcification begins around day 45, at which point pups can be counted on an x-ray — useful for predicting litter size and recognising when all pups have been delivered. From day 55 the pups gain weight rapidly, and the dam's abdomen becomes notably enlarged; introducing the whelping box at day 55 gives her time to become comfortable with it. From day 58 the pups are viable; delivery before day 58 carries risk of premature pups.
If no birth has begun by day 65, contact your vet immediately as this may indicate dystocia (difficult birth). Body temperature monitoring is a reliable sign of imminent labour: a drop in rectal temperature from ~38.5 °C to below 37.8 °C (99 °F) typically precedes whelping by 12–24 hours.
Frequently asked questions
Use the date of the first mating. Because sperm can survive in the reproductive tract for several days and the precise ovulation time is variable, subsequent matings within the fertile window are additive, but the first date gives the earliest possible conception reference point. The due-date range (day 58–65) comfortably covers most outcomes.
Ultrasound (around day 28–35) can detect pups and confirm viability but is not reliable for counting litters larger than 4–5. X-ray at day 45+ is the standard method for an accurate count because the skulls and spines are visible. Knowing the number helps you know when all pups have been born.
For the first 5 weeks of pregnancy, maintain normal adult feeding. From week 6 onward, switch to a high-quality puppy food (higher calorie and calcium density) and increase intake by 10–25% per week as the abdomen grows. By whelping she may be eating 50–75% more than her pre-pregnancy intake. Consult your vet for breed-specific advice.
Also known as
TG we-Calculate Editorial Team. (2026). Dog Pregnancy Calculator — Whelping Due Date [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/dog-pregnancy-calculator
TG we-Calculate Editorial Team. "Dog Pregnancy Calculator — Whelping Due Date." TG we-Calculate. 2026. https://we-calculate.com/calculator/dog-pregnancy-calculator.
TG we-Calculate Editorial Team, "Dog Pregnancy Calculator — Whelping Due Date," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/dog-pregnancy-calculator
@misc{wecalculate_dog_pregnancy_calculator, title = {Dog Pregnancy Calculator — Whelping Due Date}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/dog-pregnancy-calculator}}, year = {2026}, note = {TG we-Calculate} }
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