Dog Pregnancy Due Date & Whelping Window
Estimate your dog’s due date and whelping window
Dog pregnancy due date and whelping FAQ
How long are dogs usually pregnant?
Most dogs are pregnant for around 63 days from ovulation, or roughly 58–68 days when you count from a breeding or mating date. Because mating and ovulation do not always line up perfectly, any due date from a calendar is an estimate rather than a fixed appointment. Veterinary sources typically quote a normal range running from the high 50s into the high 60s in days, depending on how the start point is defined.
Should I enter mating date or ovulation date?
If you had progesterone testing done, using the ovulation or LH surge date will usually give a tighter prediction. If you only know the first mating date, enter that instead. The calculator assumes the date you enter is close to ovulation and builds a window on either side of the 63-day midpoint to help you plan.
Why is there a whelping window instead of one exact day?
Even with excellent records, real litters do not all arrive on exactly day 63. Litter size, breed, and the exact timing of ovulation versus mating can all nudge whelping earlier or later within a normal range. A whelping window is more honest: it shows when you should be ready and watching closely, with the understanding that healthy bitches may whelp a few days either side of the “headline” date.
When should I start taking rectal temperatures?
Many breeders start twice-daily rectal temperatures in the last week of pregnancy, often around day 57–58 from ovulation or first mating. A drop in temperature to around 99°F (37.2°C) or lower that then stays down often happens in the 12–24 hours before whelping. This calculator highlights a suggested “start temperature tracking” date within the prep box, but your vet’s instructions should always come first.
What are red flags that mean I should call the vet?
Contact a vet urgently if you see green/black discharge with no puppy, hard straining for more than 20–30 minutes without a puppy, more than 2 hours between puppies when more are expected, a temperature drop without labor for more than a day, or if your bitch seems very unwell, painful or confused at any stage. Due dates and windows are only guides; the mother and puppies’ behaviour always comes first.
Does litter size change the due date?
Very large or very small litters can shift the timing slightly. Big litters sometimes whelp a little earlier, small litters a little later, even when ovulation timing is known. That is one reason the whelping window in this calculator covers several days and why close observation is more important than the exact number on the calendar.
Can I use this for accidental or unplanned matings?
Yes. If you know roughly when the mating happened, plug that date in to see an approximate window. If the date is uncertain, talk to your vet about pregnancy diagnosis, timing scans, and spay options. They can help you decide what is safest and fairest for your dog and your situation.
Does this replace ultrasound or X-ray timing?
No. Ultrasound and X-ray are used to confirm pregnancy, estimate fetal age, and count skulls. This page is only a planning helper. Your vet may adjust your expectations based on what they see on scans, how your bitch is carrying, and any medical factors that could affect the timing of whelping.
How to use this dog pregnancy due date calculator
This tool turns a single date — your dog’s mating or ovulation day — into an estimated due date, a realistic whelping window, and a few milestone dates to help you get ready. It is meant as a planning aid, not a replacement for hands-on veterinary care.
1. Add the first mating, ovulation, or LH surge date
If you did progesterone testing, enter the date your vet marked as ovulation or LH surge. If you did not, use the date of the first tie or insemination. When there are multiple matings, most breeders still count from the first one; your vet can refine the timing later if needed.
2. Tap “Calculate due date” for a quick summary
The result card shows:
- The entered mating or ovulation date.
- An estimated due date 63 days later.
- A whelping watch window from about day 58 to day 68.
- Suggested prep milestones like late-pregnancy vet check and when to start temperature tracking.
Dates are shown with weekday names to make it easier to plan time off work and overnight cover, especially if you expect a large litter.
3. Use the window to plan whelping prep
Think of the window as a “eyes-on period”. In the early part of the window you might:
- Set up and line the whelping box in a quiet area.
- Finish gathering supplies: towels, scales, heat source, vet numbers, and transport plan.
- Start twice-daily rectal temperature checks if your vet recommends them.
As you move through the window, watch for nesting, restlessness, appetite changes, and the classic temperature drop, all alongside this date-based guide.
4. Copy the plan and share it with your vet
Hit the Copy summary button to send the dates to a notes app, breeder notebook or email. Sharing this with your veterinary team lets them double-check your timing, suggest any extra tests, and plan when they would like you to call if things drift past the window.
Used this way, the calculator becomes a small part of a bigger whelping plan: you bring the dates, your vet brings the medical backing, and together you give your bitch and her puppies the safest start you can.
How the dog pregnancy due date math works
Behind the scenes, this calculator uses the commonly accepted average gestation length in dogs and a simple range around that average. It is designed to be easy to sanity-check and to match the way many breeders already count weeks on a calendar.
1. Picking a starting point
The cleanest start point is ovulation or the LH surge, which are usually identified by progesterone testing. When you only know the first mating date, the calculator uses that as a proxy, understanding that actual fertilisation may be a day or two later.
2. Average gestation and the headline due date
Veterinary sources generally agree that pregnancy in the bitch lasts around 63 days from ovulation, with a tighter band (roughly 62–64 days) when hormone timing is known and a broader band when you count from breeding instead. The calculator takes the date you enter and simply adds 63 days:
Estimated due date = chosen start date + 63 days
3. Building a realistic whelping window
When you count from breeding or when ovulation timing is fuzzy, normal pregnancies can still end a few days either side of the average. To reflect that, this tool builds a whelping window by adding and subtracting a few days around the midpoint:
Early window ≈ start date + 58 days
Late window ≈ start date + 68 days
That 58–68 day span lines up with the “plus or minus about a week” guidance many breeders and vets use in practice, while still keeping 63 days as the planning anchor.
4. Prep dates for checks and temperature tracking
The calculator also marks a couple of prep milestones:
- A suggested late-pregnancy vet check date around day 50.
- A suggested start date for temperature tracking around day 57.
These are not rules; they are prompts to help you think ahead. Your own vet may shift them earlier or later depending on your bitch’s age, health, breeding history and whether there were any complications in previous litters.
The end result is a transparent, calendar-based estimate that you can combine with progesterone results, ultrasound findings and real-world labour signs to keep your bitch and her puppies as safe as possible.
References and further reading on dog pregnancy and whelping
Use these veterinary resources alongside this due date and whelping window calculator:
- VCA Animal Hospitals — Breeding for Pet Owners: Pregnancy in Dogs — outlines normal gestation ranges and explains why dates from breeding are always approximate.
- UC Davis — Normal Whelping in the Bitch — describes typical timing, temperature changes and labour stages in canine whelping.
- The Kennel Club — Whelping your first litter — practical guide to timelines, preparation, and when to worry during a dog’s pregnancy.
- PetMD — Whelping: A Guide to Help Your Dog Through Labor — accessible overview of normal gestation length, nesting behaviour, and signs of labour.
Always let your own veterinarian interpret these resources for your specific bitch and litter, especially if there are previous C-sections, singleton litters, or medical conditions in the background.