Dog Pregnancy / Whelping Due-Date Calculator
Dog pregnancy calculator. Choose what your date marks (the first mating, the LH peak, the progesterone rise or ovulation) and see the whelping window published studies measured from that day: 57 to 72 days from a first mating, 64 to 66 from the LH peak. Not veterinary advice. Runs in your browser.
Dog Pregnancy / Whelping Due-Date Calculator
How to Use the Dog Pregnancy Calculator
Choose what your date marks
The first mating, the LH peak, the initial progesterone rise or ovulation. If there were several matings, the first-mating window is the one that fits.
Enter the date
The window appears straight away, with its earliest, middle and latest dates.
Read the window, not one day
The middle date is the middle of a published range, not a due day for your dog.
Check the basis
Open “How is this calculated?” to see which study each window comes from.
Why the Count Depends on Day Zero
A dog pregnancy has no single length. It has one for each day you might count from. In a Beagle colony that Concannon and colleagues timed in 1983, whelping fell anywhere between day 57 and day 72 when counted from the first mating, but on day 64, 65 or 66 when counted from the peak of luteinising hormone (LH), the surge that triggers ovulation. The colony was the same; only the starting day changed. The AKC gives about 63 days on average from ovulation itself, which follows the LH surge by about two to two and a half days.
The mating date is the loosest of these starting points because a fertile mating can fall several days before or after ovulation, and dog sperm can stay fertile in the female tract for about a week or more. In the 1983 colony, the shortest intervals all followed late matings and the longest all followed early ones. Hormone testing narrows the count, but it dates the LH surge or the progesterone rise around ovulation, not conception: the eggs need another two or three days to mature before they can be fertilised. Kutzler and colleagues (2003), counting from the initial progesterone rise in a clinic rather than a colony, found a 65-day prediction within a day for about two thirds of 63 female dogs and within three days for all of them, so the progesterone window here is wider than the LH one.
Breed and litter size move the average too. Okkens and colleagues (2001) found breed averages more than two days apart after one timed mating, and Eilts and colleagues (2005) found small litters running about a day longer. This calculator does not adjust for either, and the window it shows is the spread one study measured, not a forecast for one dog. Everything is computed in your browser, so nothing you enter leaves your device. It is a calendar, not veterinary advice.
A dog pregnancy has no single length. It has one for each day you count from.
How the day you count from changes a dog pregnancy’s length
Counted from the first mating, whelping fell anywhere from day 57 to day 72 in Concannon’s 1983 Beagle colony.
Counted from the LH peak, the same colony whelped on day 64, 65 or 66 in all 54 timed pregnancies.
Ovulation follows the LH surge by about 2 to 2.5 days (Concannon 2002).
Dog sperm can stay fertile in the female tract for about a week or more, which is why a mating date blurs the count.
Counted from the progesterone rise, a 65-day prediction was within a day for 67% of 63 female dogs and within three days for all (Kutzler 2003).
After one progesterone-timed mating, 113 female dogs whelped 58 to 65 days later, averaging 61.4 (Okkens 2001).
In that study, breed averages ran from 60.4 days (German shepherds) to 62.8 (West Highland white terriers).
Litters of four or fewer puppies ran about a day longer on average across 764 litters (Eilts 2005).
Body temperature falls by 1°C or more in the 12 to 24 hours before whelping (Concannon and Verstegen 2004).
Counted from the LH surge, pregnancy shows on ultrasound after day 25 and on X-ray after day 46 (Concannon 2002).
Frequently Asked Questions
- It depends on the day you count from. In Concannon’s 1983 Beagle colony, whelping fell between day 57 and day 72 counted from the first mating, but on day 64, 65 or 66 counted from the LH peak. The AKC gives about 63 days on average from ovulation. The calculator asks which of these your date marks and shows the window for that day zero.
- Because a fertile mating can fall days before or after ovulation, and dog sperm can stay fertile in the female tract for about a week or more. In Concannon’s 1983 colony, every interval of 61 days or less came from a mating 3 or more days after the LH peak, and every one of 68 days or more followed a first or single mating 2 or more days before it. Concannon and Verstegen (2004) note it can reach 72 days or more from the first of several matings.
- They date the hormone events around ovulation, not conception. Ovulation follows the LH surge by about 2 to 2.5 days, and the eggs then need another 2 or 3 days in the oviducts before they can be fertilised (Concannon 2002), so the day of conception itself is not something these tests show. Choose the LH peak or the initial progesterone rise in the calculator if that is the date you have.
- Because the studies behind it measured a spread, not a day. The middle date is the middle of that published range, not a prediction for your dog. The window from ovulation is our subtraction from the LH figures rather than a measurement, and the calculator says so.
- Both move the average. Okkens and colleagues (2001) found breed averages from 60.4 days in German shepherds to 62.8 in West Highland white terriers after one timed mating, and called breed a major determinant, while noting it was not conclusively proven. Eilts and colleagues (2005) found litters of four or fewer puppies ran about a day longer on average. The windows on this page come from single studies and do not adjust for either.
- Concannon (2002) gives ultrasound after day 25 and X-ray after day 46, both counted from the LH surge, not from mating. Concannon and Verstegen (2004) put the fetal skull becoming visible on X-ray at day 44 to 48 from the LH peak. Your vet decides when to scan.
- No. It shows the spread published studies measured from each day zero, to help owners and breeders plan. Decisions about care, monitoring and whelping belong with a vet who can examine your dog.
- Completely free, with no account or usage limit. It runs entirely in your browser, collects no data, and works offline once the page has loaded.
Method & sources
How it computes
Whelping window = the day-zero date plus the range published for that day zero. First mating: 57–72 days (Concannon et al. 1983, n = 290; AKC 58–72). LH peak: 64–66 (Concannon 1983, n = 54). Initial progesterone rise: 62–68, i.e. ±3 days around Kutzler et al. 2003’s 65-day prediction, which held all 63 dogs. Ovulation: about 63 (AKC); its 62–64 window is derived, the LH range less 2–2.5 days to ovulation.
What this tool implements
- The reader chooses the day the count starts from, and each day zero has its own window; one length is never applied to two different starting events.
- A window from the first mating is wide because a fertile mating can fall days before or after ovulation and dog sperm stay fertile for about a week or more (Concannon 1983: at least 6 days; Concannon 2002: up to 8).
- Progesterone and LH testing date the hormone events around ovulation, not conception: the eggs need another 2 or 3 days to mature before fertilisation (Concannon, WSAVA 2002).
- The middle date is the middle of a published range, not a predicted whelping day for one female dog, and the ovulation window is marked as derived. The tool gives no veterinary advice.
- Breed and litter size move the average and are not adjusted for: breed averages at least 2.4 days apart in Okkens et al. 2001; litters of four or fewer about a day longer in Eilts et al. 2005.
Sources
- Concannon P, Whaley S, Lein D, Wissler R. Canine gestation length: variation related to time of mating and fertile life of sperm. Am J Vet Res 1983;44(10):1819-1821. https://pubmed.ncbi.nlm.nih.gov/6685444/
- Kutzler MA, Mohammed HO, Lamb SV, Meyers-Wallen VN. Accuracy of canine parturition date prediction from the initial rise in preovulatory progesterone concentration. Theriogenology 2003;60(6):1187-1196. https://pubmed.ncbi.nlm.nih.gov/12935856/
- Okkens AC, Teunissen JM, Van Osch W, et al. Influence of litter size and breed on the duration of gestation in dogs. J Reprod Fertil Suppl 2001;57:193-197. https://pubmed.ncbi.nlm.nih.gov/11787149/
- Eilts BE, Davidson AP, Hosgood G, et al. Factors affecting gestation duration in the bitch. Theriogenology 2005;64(2):242-251. https://doi.org/10.1016/j.theriogenology.2004.11.007
- Concannon PW. Physiology and clinical parameters of pregnancy in dogs. WSAVA Congress 2002. https://www.vin.com/doc/?id=3846292
- Concannon PW, Verstegen J. Pregnancy management in dogs and cats. WSAVA Congress 2004. https://www.vin.com/doc/?id=3852295
- American Kennel Club (Meyers H). The reproductive cycle in dogs: from breeding to birthing. Updated 18 Dec 2025. https://www.akc.org/expert-advice/dog-breeding/dog-reproductive-c…
What can make this go out of date
- None.
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