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Dog Pregnancy Calculator: Puppy Due Date

By Marcos Ortega · Updated · Runs in your browser; nothing you type is sent anywhere.

Educational estimate, not veterinary advice. These numbers come from published averages and can be wrong for your pet. Your veterinarian, who can examine your dog or cat, is the right person to decide what is healthy for them.

Dog due date calculator

–middle of the expected window

Expected window
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Days since that date
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A dog’s due date depends on which date you start counting from. The day she was bred is the date most owners know, but it’s the least precise starting point. Hormone tests done by a veterinarian narrow the window from about two weeks to about three days.

How the calculator counts

The Merck Veterinary Manual gives normal gestation in dogs (“bitches”) as:

Starting date Gestation How you know the date
First day she accepted breeding 58–72 days You saw or arranged the mating
LH surge or first rise in progesterone (above about 2 ng/mL) 64–66 days Blood tests at your vet during heat
First day of diestrus 56–58 days Vaginal cytology at your vet

The calculator adds the minimum and maximum days to your date to give the expected window, and shows the middle of that window as a single date to plan around. The middle date is our choice for convenience; Merck gives ranges, not a single day.

Window = start date + minimum days … start date + maximum days
Middle date = start date + (minimum + maximum) ÷ 2

Worked examples

Example 1: first breeding on November 2, 2026. Window: Nov 2 + 58 days = Wed, Dec 30, 2026 to Nov 2 + 72 days = Wed, Jan 13, 2027. Middle (65 days): Wed, Jan 6, 2027.

Example 2: LH surge measured on March 10, 2027. Window: + 64 to + 66 days = Thu, May 13, 2027 – Sat, May 15, 2027. Middle: Fri, May 14, 2027.

Example 3: diestrus confirmed starting March 10, 2027. Window: + 56 to + 58 days = Wed, May 5, 2027 – Fri, May 7, 2027. Middle: Thu, May 6, 2027.

Why breeding dates are imprecise

A female in heat may accept a male for several days, and conception doesn’t happen at the moment of mating. As Merck puts it, there is a disparity between when a female shows breeding behavior and when she actually conceives, which makes the due date hard to predict without ovulation timing. If an accurate date matters (for example, for a planned C-section), your vet can time ovulation with progesterone tests or identify the start of diestrus.

Getting ready

For dated milestones (when a vet can confirm the pregnancy, when puppies show on X-ray, the signs of labor), see dog pregnancy week by week.

  • Plan a vet visit to confirm the pregnancy and talk about nutrition, which changes during pregnancy and nursing. (Our dog food calculator deliberately leaves pregnancy out for this reason.)
  • Know the temperature sign. Merck notes that most dogs show a drop in rectal temperature to 98.1–100°F (36.7–37.8°C) 8–24 hours before whelping.
  • Have your vet’s number and the nearest emergency clinic ready before the window opens. If you’re worried at any point during labor, call; don’t wait.

Limitations

  • Ranges come from one authoritative reference; individual dogs can fall outside them.
  • Litter size, breed and the mother’s health can affect timing.
  • This calculator does not confirm a pregnancy. Only a veterinarian can.

Frequently asked questions

How long are dogs pregnant?

About two months, but the exact count depends on the starting point. The Merck Veterinary Manual gives 64–66 days from the LH surge (or the first rise in progesterone), 56–58 days from the first day of diestrus, and 58–72 days from the first day the female accepted breeding.

Why is the window so wide when I use the breeding date?

Because the day a female accepts breeding is not the day she conceives. She may accept a male for several days, and conception may not happen on the day of mating. Merck notes that predicting the due date without ovulation timing is difficult.

You often hear "63 days". Where does it come from?

63 days is the figure commonly quoted for gestation counted from ovulation. Because owners rarely know the ovulation date, this calculator uses the starting points the Merck Veterinary Manual gives instead.

How can I tell labor is close?

Merck notes that most dogs show a drop in rectal temperature to 98.1–100°F (36.7–37.8°C) 8–24 hours before whelping. Ask your vet how and when to take her temperature, and what signs mean you should call during labor.

How do I confirm my dog is pregnant?

Only a veterinarian can confirm it, usually with an ultrasound or a blood test after a certain stage, or with X-rays later in pregnancy to count puppies. Your vet will tell you which test makes sense and when.

Sources

  1. Merck Veterinary Manual. Whelping and Queening in Bitches and Queens. Checked October 25, 2026.

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