Dog Pregnancy Calculator
A dog mated on July 1 is due around September 2, since canine pregnancy runs about 63 days from mating. This dog pregnancy calculator estimates the whelping date, shows the realistic 58 to 68 day window, and tells you which day and trimester the pregnancy is in right now. Dog trimesters are short, about 21 days each.
Quick answer
Canine gestation averages 63 days from ovulation, and mating date is the usual stand-in.
Estimated due date
Due around September 16, 2026 (day 0 of 63)
Earliest (day 58)
2026-09-11
Latest (day 68)
2026-09-21
Days remaining
63
Trimester
1
What this tells you
- •Canine gestation averages 63 days from ovulation, and mating date is the usual stand-in.
- •Healthy litters commonly arrive anywhere from day 58 to day 68.
- •Each trimester is about 21 days. Puppies become visible on ultrasound around day 25 to 30.
- •Counting from mating adds a few days of uncertainty, since sperm can fertilize for up to a week.
How to Use
- 1Enter the mating (breeding) date.
- 2Read the estimated due date and the earliest-to-latest window.
- 3Check the current day of pregnancy and trimester.
- 4From day 58 onward, start monitoring temperature. A drop below 37.2 C (99 F) usually means labor within 24 hours.
How It Works
Formula
due date = mating date + 63 daysGestation is remarkably consistent at 62 to 64 days from ovulation across breeds and sizes. Because ovulation is rarely measured at home, the mating date plus 63 days is the standard estimate, with the 58 to 68 day range absorbing the difference between mating and actual fertilization. A vet's progesterone timing narrows the window to about 1 to 2 days.
Calculation note: values are processed in the order shown above, using the current input units.
Worked Examples
Mated July 1
63 days after July 1, with the realistic window running August 28 to September 7.
Checking progress mid-pregnancy
An ultrasound can confirm and count puppies at this stage.
Near the end
Inside the 58 to 68 day window. Nesting behavior and a temperature drop signal labor.
Dog Pregnancy Milestones
What happens at each stage of the 63-day gestation.
| Days | Stage | What to expect |
|---|---|---|
| 0-21 | First trimester | Little outward change, possible morning sickness around week 3 |
| 22-27 | Early second | Vet can palpate embryos, appetite rises |
| 25-30 | Ultrasound window | Pregnancy confirmed, rough puppy count |
| 42-49 | Third trimester | Visible belly, X-ray can count skeletons after day 45 |
| 58-68 | Whelping window | Nesting, temperature drop, then labor |
Common mistakes
- Counting from the first day of heat instead of mating. Heat starts up to two weeks before ovulation, which stretches the count badly.
- Expecting day 63 exactly. Almost half of litters arrive a few days either side, and only deliveries before day 58 or after day 68 are concerning.
- Feeding for two from day one. Extra calories only become necessary in the final third, and early overfeeding complicates whelping.