Enter the breeding date, or the ovulation date if your vet timed it with progesterone tests. You get the earliest, most likely and latest whelping dates.
Dog pregnancy calculator
Breeding or ovulation date.
Most likely due date
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From ovulation, the Merck Veterinary Manual gives 62 to 64 days. From a breeding date the range is wider, 58 to 72 days, because breeding can happen days before or after ovulation. Most dogs’ temperature drops to about 98.8°F 8 to 24 hours before whelping.
Why the window is so wide
The Merck Veterinary Manual says pregnancy lasts 62 to 64 days from ovulation, but 58 to 72 days counted from a breeding date. Sperm can survive for days, so breeding and ovulation are often not on the same day, and Merck notes that breeding dates match whelping dates poorly. If you need a tight date, ask your vet about ovulation timing.
The "most likely" date is the middle of the range for the date you entered.
Getting close
Merck reports that most dogs' rectal temperature drops to about 98.8°F (37.1°C) 8 to 24 hours before whelping. Ask your vet when to start taking it, and agree a plan in advance for when to call them during labor.
Sources
- Merck Veterinary Manual, Approximate Gestation Periods. Checked October 25, 2026.
- Merck Veterinary Manual, Whelping and Queening. Checked October 25, 2026.
Frequently asked questions
How long is a dog pregnant?
About 62 to 64 days from ovulation, according to the Merck Veterinary Manual, or 58 to 72 days counted from the breeding date.