Free dog calculator
Dog Pregnancy Calculator
This dog pregnancy calculator gives a due date window from the breeding date, or a much tighter one from your vet’s ovulation timing, using the gestation ranges in the Merck Veterinary Manual. It also lays out when a vet can confirm the pregnancy and count the puppies.
- Gestation ranges from the Merck Veterinary Manual
- Dates for every vet checkpoint
- Free, no sign-up or email
A due date is an estimate. Talk to your vet before the window opens about what to watch for, and when a late or difficult whelping needs help.
How the dog due date calculator works
Merck gives normal gestation in dogs three ways, depending on what you count from. The breeding date gives the widest window because sperm can survive in the female for a week or more, so conception can come days after the first mating. Ovulation timing pins it down.
| Counted from | Gestation (Merck) | Window width |
|---|---|---|
| First day she accepted breeding | 58 to 72 days | 15 days |
| LH surge or first rise in progesterone | 64 to 66 days | 3 days |
| First day of diestrus (cytology) | 56 to 58 days | 3 days |
Merck’s pet owner pages sum it up as about 62 to 64 days. It also notes that breed, number of previous litters and litter size can shift the length a little.
Dog pregnancy timeline
- A vet may detect the pregnancy by feeling the uterus.
- Ultrasound reliably detects pregnancy and shows the puppies are alive.
- A relaxin blood test can confirm pregnancy.
- Puppies show on x-ray.
- X-rays are the best way to count the litter.
- Rectal temperature drops to about 98.1 to 100°F in most dogs before whelping.
All of these come from Merck’s owner and professional pages. The calculator counts these days from the date you enter, so treat them as approximate when you only know the breeding date.
Labor: what’s normal and when to call
The due date gets you to the door; labor is where owners most need numbers. Merck’s owner guide splits it into three stages and gives the points where normal becomes a problem.
- 12 to 24 hours. Contractions start but can’t be seen. She may be restless, nest, hide, refuse food, vomit, pant or tremble, with clear watery discharge.
- Visible contractions and puppies. They usually come less than 1 to 2 hours apart, though that varies a lot.
- The placenta. She alternates between stages II and III, and there should be one placenta per puppy, not always right after each.
- Stage I over 24 hours, stage II over 12 to 24 hours, more than 1 to 4 hours between puppies, a puppy born dead or near death, or a mother in obvious distress.
The first week with the puppies
Merck’s advice is to weigh each puppy as soon as it’s dry, then twice a day for the first week. Any weight loss after the first 24 hours needs attention, such as extra feeding, help nursing or a vet check, and newborns should gain about 10% of their body weight a day. A kitchen scale that reads in grams makes that easy to see.
Small breeds need one more watch item. After delivery, the demands of nursing can drop the mother’s blood calcium too low, and Merck says this is most common in dogs under 45 pounds. Every dachshund falls in that range, so ask your vet before the due date what signs to watch for.
What changes the date
Which date you have
A breeding date leaves about two weeks of uncertainty. Merck says breeding dates don’t line up with whelping as closely as actual ovulation does.
Litter size and breed
Merck lists breed, parity and litter size as factors in gestation length.
Planned C-section
Merck says an elective cesarean is safe after 62 days of gestation. Earlier, the puppies’ lungs may not be ready.
False alarms
Merck notes that 60% of dogs bred by accident don’t become pregnant, so confirm with your vet before planning around a date.
For more on what to expect from a dachshund litter, see our dachshund pregnancy guide.
Dog pregnancy questions
How long are dogs pregnant?
About 62 to 64 days on average, by Merck’s owner guide. Counted from the first breeding, normal runs anywhere from 58 to 72 days.
How soon can a vet confirm my dog is pregnant?
Ultrasound reliably shows it from about day 25 to 35, and a relaxin blood test works from about day 30 to 35. A vet may feel it by hand around day 21.
Could it be a false pregnancy?
It could. Merck calls pseudopregnancy fairly common in unspayed females. Every female that isn’t pregnant goes through the same hormonal phase after a heat, diestrus, which Merck’s owner guide says usually lasts about 2 months, and signs show up toward its end. That’s close to when puppies would have been due, so a dog with a due date from this calculator and no puppies on the scan may be going through exactly this. It’s a question owners post when a dog suddenly stops eating. Merck lists restlessness, poor appetite, less activity, licking at the belly, maternal behavior, weight gain, enlarged mammary glands and milk. Most signs go away without treatment. If she’s making milk, don’t express it; Merck says that keeps production going. If she stops eating or drinking, call your vet.
How do I know labor is close?
Most dogs’ rectal temperature drops to about 98.1 to 100°F 8 to 24 hours before whelping, according to Merck. Checking temperature once the due window opens gives you that warning.
Sources
- Merck Veterinary Manual, Pseudopregnancy in Small Animals (reviewed July 2023): how common it is, timing, signs, not milking out the glands.
- Merck Veterinary Manual, Whelping and Queening in Dogs and Cats: gestation by reference date, temperature drop, elective cesarean timing (read October 2026).
- Merck Veterinary Manual pet owner version, Management of Reproduction in Dogs: diestrus length in non-pregnant dogs, average length, detection days, misbreeding figure, labor stages, newborn weighing and low calcium after delivery (read October 2026).