Dog Pregnancy Calculator
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Enter the mating, LH surge or ovulation date to see your dog's expected whelping window, a vet calendar and labor signs.
Quick answer: a dog is pregnant for about 63 days from ovulation. This dog pregnancy calculator turns a mating date into a whelping window of 56 to 69 days, or 64 to 66 days after an LH surge, so a mating on June 1 gives July 27 to August 9. Add an LH surge or ovulation date to narrow the window.
📐 Formula
Mating date: first mating + 56 days to last mating + 69 days (one mating: 56 to 69 days), most likely 63 days. LH surge date: + 64 to 66 days, most likely 65. Ovulation date: the LH surge is the ovulation date − 2 days, so + 62 to 64 days, most likely 63.
How to use the dog pregnancy calculator
Pick what your date marks
Choose First mating date, LH surge date or Ovulation date. An LH surge or ovulation date confirmed by your vet gives the narrowest window.
Enter the date
Type or pick the date. A mating date cannot be in the future, and the date must fall within the last 150 days.
Add a last mating date if there was more than one
Leave the optional box blank for a single mating. If you mated her on several days, enter the first date above and the last date here.
Read the window and the calendar
The result shows the expected whelping window, the most likely date and where your dog is today. The calendar lists dates for palpation, ultrasound, relaxin and X-ray checks.
How long is a dog pregnant?
A dog is pregnant for about 63 days, or nine weeks, counted from ovulation. Veterinary reproduction research counts from the LH surge instead, the rise in luteinizing hormone that triggers ovulation about two days later, and finds whelping falls 64 to 66 days after it in nearly all dogs. Counted from a single mating, the interval is much looser, from 56 days after a late mating to 69 days after an early one, because the mating date and the ovulation date rarely match.
That gap is why this dog gestation calculator shows a window and a most likely date rather than one "due date". Merck's Veterinary Manual also notes that breed, parity and litter size can influence the length, which is one more reason to plan around a few days, not a single day.
Dog pregnancy calculator by days: what to enter
The date you know decides how tight the window is. Counting in days from the date you enter, the calculator uses these rules.
| Date you enter | Window | Source |
|---|---|---|
| First mating date | 56 to 69 days after mating | Concannon (WSAVA 2002): single mating can range from 56 to 69 days |
| LH surge date | 64 to 66 days after the surge | Concannon (WSAVA 2002): 64, 65 or 66 days in nearly all dogs |
| Ovulation date | 62 to 64 days after ovulation | Our arithmetic: LH surge to ovulation is about 2 days |
A mating date is the easiest to know and the loosest. A bitch can mate from about 5 days before ovulation to 3 days after it, and sperm can stay fertile for up to 8 days, so two dogs mated on the same day can whelp days apart. An LH surge or ovulation date from a progesterone test removes that uncertainty. Your vet can arrange the test during heat.
Dog due date calculator: worked example
A bitch is mated on June 1. The window runs from June 1 + 56 days to June 1 + 69 days: July 27 to August 9, with a most likely date of August 3 (63 days). If the mating was spread over June 1 and June 4, the window becomes July 27 (first mating + 56) to August 12 (last mating + 69).
Now say a progesterone test puts the LH surge on June 4. Whelping falls 64 to 66 days later: August 7 to August 9, with August 8 the most likely day. An ovulation date of June 6 gives the same window, because ovulation follows the surge by about two days. Three days of window instead of fourteen is the payoff of a progesterone test.
Dog pregnancy calculator from ovulation and the LH surge
Ovulation timing is the most reliable anchor, and vets measure it with serial progesterone blood tests during heat. The LH surge is the hormone peak that comes first, and vets estimate its date from the progesterone results. Enter that date with the matching option and the calculator does the counting. If you only have the ovulation date, it works backward two days to the surge before adding 64 to 66 days.
Dog pregnancy week by week
Day counts in veterinary sources run from the LH surge, so the table below uses that clock. With a mating date only, the calendar in the result assumes mating happened at ovulation, so real dates may sit a few days earlier or later.
| Week | Days | What happens |
|---|---|---|
| Weeks 1 to 2 | 0 to 14 | Embryos travel down the uterine tubes and enter the uterus around day 10 to 12. Nothing is visible from outside. |
| Week 3 | 15 to 21 | Pre-implantation swellings can be felt around day 18, and the embryos begin attaching around day 21. Ultrasound can first see embryonic vesicles at day 18 to 20 on high-resolution equipment. |
| Week 4 | 22 to 28 | Implantation is complete by about day 22 (Merck puts it at about day 18). A heartbeat shows on ultrasound at day 24 to 25, and ultrasound is reliable from about day 25. |
| Week 5 | 29 to 35 | A relaxin blood test is diagnostic after day 30. Fetal movement appears on ultrasound around day 35, and palpation gets harder after day 35 to 38. |
| Week 6 | 36 to 42 | The embryo is clearly longer than the placental girdle after day 42. |
| Week 7 | 43 to 49 | Skeletons start to show on X-ray (Merck: day 42 to 45; VIN: day 46) and are prominent by day 47 to 48. |
| Weeks 8 to 9 | 50 to 66 | X-ray after day 55 is the best way to count puppies. Whelping usually falls on day 64 to 66, and body weight typically rises by 20 to 55 percent over the whole pregnancy. |
When can a vet confirm a dog is pregnant?
No calculator can tell you whether conception happened. A mating date does not guarantee pregnancy, and everything above is conditional on there being a pregnancy. A vet can confirm it by any of these methods.
| Method | When | Notes |
|---|---|---|
| Abdominal palpation | About day 20 to 35 | Needs a trained vet and a calm dog. Becomes difficult after day 35 to 38. |
| Ultrasound | From about day 25 | Can show a heartbeat at day 24 to 25. Merck reports false negatives before day 21. |
| Relaxin blood test | After day 22 to 30 | Merck gives about 22 to 27 days and Concannon (WSAVA 2002) says after day 30. Ask the lab. |
| X-ray | From about day 42 to 46 | Merck says skeletons show from about day 42 to 45 and Concannon (WSAVA 2002) says after day 46. After day 55 it gives the best litter count. |
The sources differ on the earliest relaxin timing: Merck says after 22 to 27 days of gestation, while Concannon (WSAVA 2002) says after day 30 counted from the LH surge. Ask your vet which method suits your dog and when to book it.
Signs a dog is about to whelp
- Extreme nesting, shredding bedding, discomfort and panting, 6 to 12 hours before labor and sometimes up to 24 to 36 hours.
- A fall in rectal temperature to 98.1 to 100°F, which Merck places 8 to 24 hours before whelping. Cornell puts the dip below 99°F and says it lasts around eight hours. A dog's normal range is 100 to 102.5°F.
- A clear or white sac at the vulva means whelping should be imminent. Green discharge should be followed immediately by a puppy.
- Subtle signs such as a relaxed perineum or swollen mammary glands are not sensitive or specific, according to Merck, so do not rely on them alone.
The three stages of labor
Cornell describes three stages: uterine contractions with the cervix opening, delivery of each puppy and delivery of the placentas. The second and third stages happen together in dogs. Each puppy usually takes 0 to 30 minutes to arrive, and up to two hours between puppies is considered normal. Call your veterinarian if more than two hours pass between puppies, and keep the numbers for your vet and an emergency clinic where you can reach them after hours.
Preparing a whelping area
Set up a quiet, warm, enclosed space with washable bedding at least a week before the window opens, and get your dog used to it. Keep towels, a clean scale for newborns and your vet's contact details nearby. If your vet recommended an ultrasound or X-ray, book it using the calendar above so you know the litter size to expect. A nursing mother needs far more food than normal, so rework her daily amount with our Pet Food Calculator.
Does breed change the due date?
Veterinary sources give one window for all dogs and publish no breed table, and Merck notes that breed, parity and litter size can also influence gestational length. This page has no breed-by-breed litter table because we could not find a primary source for one. If you are timing a first breeding, our Dog Age Calculator shows where the dam sits on the human-year scale for her size.
Dog pregnancy calculator for the UK, Australia and Canada
Gestation does not change with country, so the same day counts apply in the US, UK, Australia and Canada. Dates on this page are written month first. Ask your own vet about progesterone testing and out-of-hours emergency care where you live. For human pregnancy dates there is a separate Due Date Calculator.
Frequently asked questions
About nine weeks, or 63 days from ovulation. In practice, plan for a stretch, not a day: a June 1 mating has a most likely date of August 3 but could whelp anywhere from July 27 to August 9. Ask your vet about a progesterone test if you want a tighter answer.
Treat it as a planning window. In the June 1 example the window spans 14 days, so book your vet's checks around the most likely date but keep the whole window free.
Use the progesterone-based date, either the LH surge or ovulation, because it pins down ovulation. Choose the mating option only when no test was done.
No home method confirms it. Only a vet check settles it: palpation, ultrasound or a relaxin blood test, at the timings shown on this page.
Start taking your dog's rectal temperature once the window opens. Cornell gives 100 to 102.5°F as normal for a dog, and a reading below 99°F means labor may start within 24 hours.
Veterinary sources give one window for all dogs, so this page uses the same one for every breed, although Merck notes that breed, parity and litter size can influence gestational length. A June 1 mating gives July 27 to August 9 here for any dog, and a progesterone-timed date (64 to 66 days from the LH surge) gives a narrower window than a mating date. If an earlier litter came early or late, tell your vet, who can time the ultrasound and X-ray around that history.
Write down the time each puppy arrives, and call your vet if two hours pass without one. Green discharge should be followed immediately by a puppy, so call if one does not appear.
Enter the first mating date and put the last in the optional box. The window opens 56 days after the first mating and closes 69 days after the last, so every extra day between matings pushes the end of the window a day later. If the dates are spread out, a progesterone test is the way to tighten it.
The calculator counts in days from the date you enter and lists a dated calendar of vet checks. The week-by-week table below the calculator shows what a vet can see in each week, and the page runs in your browser, so there is no app to install.
Sources and methodology
Day counts and the 56 to 69 day single-mating range come from Concannon, "Physiology and Clinical Parameters of Pregnancy in Dogs" (Cornell University, WSAVA 2002 Congress). Pregnancy checks come from the Merck Veterinary Manual and Concannon (WSAVA 2002). The 63-day average from ovulation is from Cornell's Riney Canine Health Center page on the normal whelping process. The temperature drop to 98.1 to 100°F, 8 to 24 hours before whelping, is from the Merck whelping page, and the Riney page adds a dip below 99°F lasting about eight hours. The stages of labor come from the Riney page. The 62 to 64 day window from ovulation is our own arithmetic from the 64 to 66 day figure and a two-day LH-to-ovulation gap.