Dog Due Date Calculator
Everything is calculated in your browser. The dates you enter are never sent anywhere — no signup, no account, nothing stored.
How the due date is worked out
One piece of arithmetic: first mating date + 63 days = estimated due date. Sixty-three days is the average length of a dog's pregnancy measured from ovulation, and it barely varies between dogs. This dog due date calculator does the count instantly and then shows the two dates that matter almost as much — the earliest and latest she could reasonably give birth.
Why you also get an earliest and a latest date
Because fertilization does not necessarily happen on the mating day. Sperm can wait inside the female for several days, and her eggs need about two days after ovulation before they can be fertilized at all. So the same pregnancy can honestly start several days after the mating you saw — which is why real litters arrive from day 58 to day 68. Plan around the window; celebrate the due date as the most likely single day, not a promise.
Worked example
First mated Friday, August 14, 2026 → due date Friday, October 16, 2026; earliest likely Sunday, October 11; latest likely Wednesday, October 21. If she was also mated on August 17, enter it as the last mating date and the latest date extends to October 24 — the due date itself does not move.
What to have ready by the earliest date
Be ready by day 58, not day 63: whelping box set up and familiar, supplies gathered (towels, heating pad, sterile gloves, bulb syringe, scale, puppy formula), her temperature routine running since day 56, and your vet's number where you can find it at 3 a.m. The full dated list is our whelping preparation checklist.
How accurate is this date?
As accurate as mating-date math can be — which means a well-understood window, explained honestly in our dog due date accuracy guide. The one genuine upgrade is knowing the ovulation date: if your vet ran progesterone tests during the heat, use the dog pregnancy calculator from ovulation for a window of days instead of ten.
Frequently asked questions
How do I work out my dog's due date?
Take the first mating date and add 63 days — that is the standard estimate. Then treat days 58–68 as the window to be ready in. The calculator above does the count for you and shows the due date, the earliest and latest likely dates, and how many days are left.
What if my dog was mated on more than one day?
Enter the first mating date and the last one. The due date still counts from the first mating, but the latest likely date extends to 68 days after the last mating, because the later mating may be the one that took. The window widens — that is normal and expected.
My dog is past her due date. Should I worry?
Not on day 63 itself — the due date is the middle of a window, not a deadline. Whelping any time up to day 68 from the first mating can be normal. If she passes day 68 with no signs of labor, call your vet the same day for advice.
Can an ultrasound give a more exact due date?
It can narrow things. Measurements taken on an ultrasound before about day 40 let a vet estimate gestational age more closely than mating dates alone, and ovulation timing narrows it further. Read our due date accuracy guide, or use the from-ovulation calculator if you had progesterone testing done.
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