Free Dog Pregnancy Due Date calculator with clear step-by-step results.
Canine gestation averages 63 days from ovulation but can appear to span 58 to 68 days when counted from breeding, because sperm survive several days in the reproductive tract. The window either side of the due date is therefore wider than the average suggests, and day 45 is when skeletons are mineralised enough to count puppies on radiograph.
Due date
Due date = breeding date + gestation days (63 by default)
Whelping window
Viable delivery spans breeding date + 58 to breeding date + 68 days
An estimate from average canine gestation. Progesterone timing and veterinary examination are far more accurate, and dystocia is a life-threatening emergency for both dam and puppies.
The 63-day average is measured from ovulation, not mating. Progesterone testing pinpoints ovulation and narrows the estimate to within a day or two.
Delivery before day 58, more than 24 hours past a temperature drop with no labour, or strong straining for over 30 minutes without a puppy all warrant immediate veterinary attention.