Dog Pregnancy Calculator
Expected whelping date and gestation milestones from the LH surge — 63 days median, 58–68 day window.
How this calculator works
63-day mean gestation from LH surge (range 58-68); stage milestones from MSD Veterinary Manual.
How this calculator works
Gestation counts from the LH surge, not the mating date. The median is 63 days; the normal window is 58–68. Milestones are from the MSD Veterinary Manual.
- 1
expectedWhelping = lhSurge + 63 days
Canine gestation averages 63 days from the LH surge at ovulation, with a typical range of 58–68 days. The LH surge is the reliable anchor — mating dates can be several days off from ovulation.
MSD Veterinary Manual; Concannon et al. canine reproduction literature.
- 2
whelpingWindow = lhSurge + [58, 68] days
The 10-day window spans nearly all normal canine pregnancies. A delivery outside this window warrants veterinary attention — either the dating is off or something is unusual about the pregnancy.
MSD Veterinary Manual.
- 3
milestones = msdStageTable
MSD publishes a stage-by-stage embryonic and fetal development timeline. We render the milestones alongside the countdown so owners can connect the day-count to what is actually happening in the pregnancy.
MSD Veterinary Manual — Dog Pregnancy.
When to use this calculator
Use this when you know (or have a reasonable estimate of) the LH surge date for your dog, and you want to plan the whelping preparation timeline — kit, nesting area, vet handoff — against a specific window rather than a vague "about two months."
If you only know the mating date, start the countdown there as an approximation, but expect 2–5 days of uncertainty in either direction. A progesterone timing test with your veterinarian can tighten the LH-surge anchor significantly.
Frequently asked
Is 63 days exact?
It is a median. Normal canine pregnancies fall within a 58–68 day window. Delivery before day 58 is typically considered premature; after day 68 warrants veterinary evaluation. Your veterinarian will use ultrasound and hormone timing to confirm gestational age if precise dating matters.
Why LH surge instead of mating date?
Canine sperm can survive in the reproductive tract for several days after mating, and ovulation (triggered by the LH surge) can occur days after the mating itself. That makes mating date a noisy anchor; the LH surge is the reliable one. Your veterinarian can measure the LH surge via progesterone testing.
What should I be doing during the pregnancy?
Work with your veterinarian on a prenatal plan: nutrition adjustment during the last trimester, ultrasound or X-ray confirmation of litter size before whelping, and a whelping-setup checklist. This calculator tells you the timeline; your veterinarian provides the care plan.
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Sources
The formula and life-stage logic on this page cite the peer- reviewed research and veterinary-organization guidelines below.
- Peer-reviewed · 2011Concannon PW — Reproductive cycles of the domestic bitch
Canonical description of the canine estrous cycle and gestation timeline from LH surge.
- Veterinary referenceMSD Veterinary Manual — Dog Pregnancy
63-day mean gestation, 58–68 day whelping window, and milestone timeline.
- Veterinary guidelineAVMA — Breeding Practices Guidance
Veterinary-prenatal-care framing referenced on this page.