Dog pregnancy calculator — due date & puppy development

Free online dog pregnancy calculator. Enter the mating date and instantly find out the expected whelping date, when to schedule an ultrasound and X-ray, and follow your puppies' development week by week — from fertilisation to birth.

Mating date

Puppy development week by week

Week 1 — day 1–7

~ grain of sand

After mating, fertilisation occurs. Sperm travel up the oviduct to the eggs, where fertilisation takes place. Fertilised eggs begin to divide.

Recommendation: Normal routine, quality food. No special changes are needed. Avoid vaccinations and chemical treatments.

Week 2 — day 8–14

~ poppy seed (0.5 mm)

Embryos travel down the oviduct toward the uterus. Cells continue dividing and the germ layers that will form organs begin to take shape.

Recommendation: No significant changes. Provide a calm environment, avoid stress and excessive physical exertion.

Week 3 — day 15–21

~ grain of rice (5 mm)

Embryos implant in the uterine wall (around day 16–20). The placenta begins to form and will supply the foetuses with nutrients. The dam may have a reduced appetite or morning sickness.

Recommendation: Offer smaller meals more often. If she refuses food, don't panic — it's normal. Continue to avoid vaccinations.

4 Ultrasound

Week 4 — day 22–28

~ hazelnut (1.5 cm)

Organs, eyes and the spine develop. Around day 25 an ultrasound can confirm pregnancy and detect foetal heartbeats. Embryos are about 1.5 cm long.

Recommendation: Ultrasound at the vet (day 25–30) to confirm pregnancy. Limit jumping and rough play.

Week 5 — day 29–35

~ walnut (3–4 cm)

Foetuses grow rapidly — paws, claws and whiskers develop. The dam's belly starts to visibly enlarge. Foetuses measure around 3–4 cm.

Recommendation: Gradually increase protein intake. Begin transitioning to a higher-quality puppy formula. Shorter, more frequent walks.

Week 6 — day 36–42

~ tangerine (6–9 cm)

Foetuses are fully formed — with developed coats, pigmentation and sex organs. They gain weight quickly. The dam visibly gains weight and her belly is noticeably larger.

Recommendation: Feed 3× daily in smaller portions (puppy food). She needs more energy but has less stomach space. Provide a calm resting area.

7 X-ray

Week 7 — day 43–49

~ lemon (10–14 cm)

The puppies' skeletons mineralise — from day 45 they are visible on an X-ray, allowing an accurate puppy count. Foetuses measure around 7–9 cm and their coat is fully developed.

Recommendation: X-ray at the vet (day 45–50) to count the puppies. Prepare the whelping box. Limit physical activity to calm walks.

Week 8 — day 50–56

~ mango (15–18 cm)

Puppies are almost fully developed and assume the whelping position. The dam begins nesting — looking for a quiet spot and may become restless. The mammary glands fill.

Recommendation: The whelping box should be ready and the dam should get used to it. Start measuring rectal temperature twice a day. Prepare everything needed for whelping.

9 Whelping!

Week 9 — day 57–65

~ small melon (20 cm, 350–500 g)

The puppies are ready to be born! The dam may refuse food, become restless and seek privacy. A drop in body temperature below 37 °C signals whelping within 12–24 hours. Golden Retriever litters typically number 6–10 puppies.

Recommendation: Watch for the temperature drop (below 37 °C = whelping within 24 hours). Keep the vet's number handy. Ensure calm and warmth. If contractions last more than 2 hours without a puppy being born, call the vet.

What to prepare for whelping

Whelping box (min. 120×120 cm for a Golden Retriever)
Clean towels and pads
Digital thermometer
Disinfectant and sterile scissors
Scale for weighing puppies
Coloured collars/ribbons to identify puppies
Vet's and emergency phone numbers
Puppy milk replacer (just in case)

Golden Retriever specifics

Gestation length: 58–65 days (average 63 days)
Typical litter size: 6–10 puppies
Newborn puppy weight: 350–500 g
Golden Retrievers are generally excellent mothers
C-section is less common in this breed
After whelping the dam needs 3–4× more energy

Puppy development in the womb

Fascinating National Geographic footage showing how puppies develop from fertilisation to birth.

Frequently asked questions about dog pregnancy

How long is a dog pregnant?

A dog's pregnancy (gestation) lasts an average of 63 days (9 weeks) from the mating date. Whelping may occur between day 58 and day 65. Golden Retrievers average 63 days of gestation.

When to do an ultrasound on a pregnant dog?

An ultrasound can be performed between day 25 and 30 after mating. At this stage the vet can confirm pregnancy and detect foetal heartbeats.

When to do an X-ray on a pregnant dog?

An X-ray is recommended from day 45 of pregnancy. It allows accurate counting of puppies based on visible skeletal structures.

How many puppies does a Golden Retriever have?

A Golden Retriever typically has 6 to 10 puppies per litter. A newborn puppy weighs 350–500 g. Litter size depends on the dam's age, health and genetics.

How do I know my dog is about to give birth?

The main sign of imminent whelping is a drop in the dam's body temperature below 37 °C (98.6 °F), signalling birth within 12–24 hours. She may become restless, refuse food and seek a secluded spot.

When can puppies go to their new homes?

Puppies can leave for their new homes at the earliest at 8 weeks of age (56 days after birth). Until then they need to stay with their mother for proper physical and psychological development.

Disclaimer: This guide is for informational purposes only. Every pregnancy is unique. Always consult your veterinarian and follow their recommendations.

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