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Dog Pregnancy Calculator

Dog due date 63 days after mating (day 56 to day 70) or after a progesterone-timed ovulation (day 61 to day 65), from Cornell veterinary figures. How it works

Use the Dog Pregnancy Calculator

Estimated due date
Select the mating date to estimate the due date

63 days after the mating date entered

Cornell University gives a dog's pregnancy as an average of 63 days from ovulation. This estimate counts from the mating date you entered, and breeding dates are often inaccurate: Cornell gives 63 ± 7 days from the first breeding, which is the range shown (day 56 to day 70). Consult your veterinarian for prenatal care and to confirm the date.

About the Dog Pregnancy Calculator

A dog’s due date is 63 days after the mating date, and the tool shows day 56 to day 70 as the range. A mating on March 1, 2026 gives a due date of May 3, 2026, earliest April 26 and latest May 10. Cornell’s 63 days is counted from ovulation, so a date counted from mating is less exact: Cornell gives 63 ± 7 days from the first breeding. With a progesterone-timed ovulation date the due date is still day 63 and the range narrows to day 61 to 65: an ovulation on March 1, 2026 gives May 3, range May 1 to May 5.

Dog due date by mating date

Mating dateEarliest (day 56)Due date (day 63)Latest (day 70)
January 15, 2026March 12, 2026March 19, 2026March 26, 2026
February 1, 2026March 29, 2026April 5, 2026April 12, 2026
March 1, 2026April 26, 2026May 3, 2026May 10, 2026
April 10, 2026June 5, 2026June 12, 2026June 19, 2026
June 1, 2026July 27, 2026August 3, 2026August 10, 2026
August 20, 2026October 15, 2026October 22, 2026October 29, 2026
November 5, 2026December 31, 2026January 7, 2027January 14, 2027
December 20, 2026February 14, 2027February 21, 2027February 28, 2027

Every date is the mating date plus 56, 63 or 70 calendar days. The page notes that breeding dates are often inaccurate and to consult your veterinarian to confirm the date.

Pregnancy milestones a vet can check

MilestoneDay of pregnancySource
Uterine swellings can be felt by palpationFrom about day 21; harder to feel after days 35 to 38Merck Veterinary Manual
Relaxin blood test is reliableAfter days 22 to 27Merck Veterinary Manual
Ultrasound is best performedDays 25 to 35 (before day 21 it can miss a pregnancy)Merck Veterinary Manual
Puppy skeletons show on an X-rayFrom about days 42 to 45; clear by days 47 to 48Merck Veterinary Manual
X-ray for the best puppy countAfter day 55Merck Veterinary Manual
Rectal temperature drops below 99 °FWithin 24 hours of whelping, usually for about 8 hoursCornell Riney Canine Health Center

Merck gives these as days of gestation without saying whether they count from ovulation or breeding, so read them against the range, not the single due date. The calculator shows only the due date and its range; it does not list these milestones.

Methodology

Due date = mating date + 63 days. Earliest = mating date + 56 days (63 − 7). Latest = mating date + 70 days (63 + 7). From an ovulation date: due date = ovulation + 63 days, earliest + 61, latest + 65 (63 ± 2). Cornell University College of Veterinary Medicine gives an average of 63 days from ovulation, 63 ± 7 days from the date of the first breeding and 63 ± 1 to 2 days from a progesterone-confirmed ovulation.

How to use this tool

  1. Choose Mating date, or Ovulation date if progesterone testing timed the ovulation.
  2. Enter the date. The field starts on today’s date.
  3. Read the estimated due date, 63 days after the date entered.
  4. Read the earliest and latest dates: day 56 to day 70 from a mating date, day 61 to day 65 from an ovulation date.

Frequently asked questions

How long is a dog pregnant?
Cornell University’s College of Veterinary Medicine gives an average of 63 days from ovulation. Counted from the first breeding, it gives 63 ± 7 days, because the breeding date often does not match the day the dog ovulated.
How do I calculate a dog’s due date from the mating date?
Add 63 days to the date. A mating on March 1, 2026 gives May 3, 2026, and a mating on June 1, 2026 gives August 3, 2026. Counting by hand, 63 days is nine weeks, so the due date falls on the same weekday as the mating.
Why does the tool show a range 14 days wide?
The range is the Cornell figure for a breeding date: 63 days plus or minus 7. That is day 56 to day 70. If the mating date is exact the due date is the best single figure, and the range tells you how far the real date can sit from it.
What if I know the ovulation date?
Choose Ovulation date. Cornell gives 63 ± 1 to 2 days from the date progesterone testing shows ovulation and calls ovulation timing the most reliable way to predict the date. The tool shows day 63 with a range of day 61 to day 65: an ovulation on June 1, 2026 gives August 3, range August 1 to August 5.
Which date do I enter if the dogs mated more than once?
Cornell counts from the first breeding. The tool counts from whatever date you enter, so enter the first mating date and use the range. Ask your veterinarian to confirm the date and for prenatal care.
When can a vet confirm that my dog is pregnant?
The Merck Veterinary Manual puts ultrasound at its best from days 25 to 35 of gestation (before day 21 it can miss a pregnancy), a relaxin blood test as reliable after days 22 to 27, and puppy skeletons on an X-ray from about days 42 to 45. An X-ray after day 55 gives the best count of puppies.

What to watch for as the due date nears

Have the whelping area ready before the earliest date, day 56. Cornell's whelping guide gives these signs and limits:

  • An ultrasound about halfway through the pregnancy can estimate the due date more closely than the mating date.

  • Normal rectal temperature is 100 to 102.5°F. It drops below 99°F within 24 hours of birth, usually for about eight hours, though the drop is easy to miss.

  • Nesting, restlessness and panting usually start 6 to 12 hours before the first puppy.

  • Green discharge should be followed quickly by a puppy. Puppies usually come 0 to 30 minutes apart; call your vet if more than two hours pass between puppies.

Why the range is day 56 to 70, or 61 to 65

due date = mating date + 63 days, with earliest = + 56 days and latest = + 70 days.

The 63 days is counted from ovulation, and a mating date is only a stand-in for it. Cornell notes that breeding dates are often inaccurate, which is why it widens the figure to 63 ± 7 days when it is counted from the first breeding. If progesterone testing timed the ovulation, choose Ovulation date: the due date is still day 63 and the range narrows to day 61 to 65, Cornell's 63 ± 1 to 2 days.

Example: a mating on March 1, 2026 gives a due date of May 3, 2026, earliest April 26 and latest May 10. A mating on February 1, 2026 gives April 5, 2026; an ovulation on March 1, 2026 gives May 3, range May 1 to May 5.

After whelping, Cornell describes a green to red or brown discharge that usually lasts about three weeks and can go on for up to eight. A foul smell or a rising amount of discharge is a reason to see the vet.

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