Dog Pregnancy Calculator
Find the due-date window for your dog from the date you know, and see when a vet can confirm the pregnancy.
Pick a date to see the due-date window.
Not veterinary advice. Due dates are a window from veterinary references. Your vet should confirm the pregnancy and plan the birth, especially for a first litter, a small or flat-faced breed, or a female with health problems. Read the full disclaimer.
Which date to count from
| Date you have | Days to birth |
|---|---|
| LH surge or progesterone rise (from hormone tests) | 64 to 66 |
| First day of diestrus (from vaginal cytology) | 56 to 58 |
| First mating she accepted | 58 to 72 |
Hormone tests are the most precise way to date a pregnancy. The LH surge and the first rise in progesterone happen around ovulation, and birth follows about 64 to 66 days later. If your breeder or vet did not run them, the first-mating window is the one to use, and it is honest about how much it can vary.
Planning a litter? A vet can time the mating with hormone tests and tell you when to schedule the checks above. Already expecting? Switch to the dog calorie calculator to see how much the mother’s food changes with her weight, and ask your vet for the pregnancy and nursing amounts.
Frequently asked questions
How long is a dog pregnant?
It depends on which date you count from. The Merck Veterinary Manual gives 64 to 66 days from the LH surge or the first rise in progesterone, 56 to 58 days from the first day of diestrus, and 58 to 72 days from the first time the female allowed mating. The often-quoted "63 days" is not a figure Merck uses.
Why is the window from the first mating so wide?
Merck explains that heat behavior and the real moment of conception do not line up closely in dogs, and sperm can stay alive in the female for a week or more. Mating dates and conception dates therefore do not correlate closely enough to predict the birth to the day. Hormone testing narrows the window to about two days.
When can my vet confirm the pregnancy?
Merck lists a relaxin blood test that detects pregnancy after about day 22 to 27, and says ultrasound is best done at 25 to 35 days of gestation, with false negatives possible before 21 days. The skeleton shows on X-ray from about day 42 to 45, and an X-ray after day 55 is the best way to count the puppies.
What if she goes past the window?
Call your vet. The dates here are a normal window, not a deadline you can wait out, and only your vet can say whether a late dog needs a check.
Can I use this for a planned cesarean?
No. A planned cesarean needs ovulation timing from hormone tests and a vet's plan. Merck notes that late X-rays and fetal development are used to confirm readiness when ovulation was not timed.
Sources
- Whelping and Queening in Bitches and Queens. Merck Veterinary Manual. Read 2026-11-08. Used for: Bitch: 56 to 58 days from the first day of diestrus, 64 to 66 days from the LH surge or progesterone rise, 58 to 72 days from the first accepted mating. Queen: 64 to 66 days from the LH surge triggered by mating.
- Pregnancy Determination in Bitches and Queens. Merck Veterinary Manual. Read 2026-11-08. Used for: Implantation at about 18 days (bitch) and 14 days (queen); relaxin test after 22 to 27 days; ultrasound best at 25 to 35 days; skeleton visible on X-ray from about day 42 to 45, and X-ray after 55 days is best for litter size.
Facts last checked against their sources on November 8, 2026. Read how the numbers are built on the sources and method page.