CalcKitDog Due Date Calculator
Your dog’s breeding date
Gestation varies by dog, so the due date is an estimate. If anything seems off, or the due date passes with no labor, call your vet.
Example: ovulation September 1, 2026 — due November 3, 2026, with a whelping window of October 29 to November 8, 2026.
Behind the numbers
How a dog’s due date is calculated
A dog’s pregnancy lasts about 63 days from ovulation — roughly 9 weeks. Because ovulation is hard to pin down without progesterone testing, most dogs whelp somewhere between 58 and 68 days after ovulation, so the due date is best thought of as the middle of that 10-day whelping window. If you only know the mating date, the same 63 days are used as an estimate, but it is less exact: ovulation can follow mating by a day or two. Breed barely changes gestation — it is about 63 days for almost all breeds — so the breed you enter is shown for reference and does not change the date.
Worked example: ovulation on September 1, 2026 + 63 days = November 3, 2026. The whelping window runs from day 58 (September 1 + 58 = October 29, 2026) to day 68 (September 1 + 68 = November 8, 2026). Milestones from the same date: ultrasound on day 28 = September 29, 2026, X-ray on day 45 = October 16, 2026, and nesting prep on day 56 = October 27, 2026.
Examples
Example due dates
| Date known | Date | Due date | Whelping window |
|---|---|---|---|
| Ovulation | September 1, 2026 | November 3, 2026 | October 29 – November 8, 2026 |
| Ovulation | January 15, 2026 | March 19, 2026 | March 14 – March 24, 2026 |
| Mating | April 10, 2026 | June 12, 2026 | June 7 – June 17, 2026 |
| Ovulation | July 1, 2026 | September 2, 2026 | August 28 – September 7, 2026 |
Milestones
Pregnancy milestones by day
| When | What happens |
|---|---|
| Days 1–17 | Embryos travel to the uterus and settle in; most dogs show no outward signs yet. |
| Days 18–21 | Implantation; some dogs have a short spell of morning sickness around week 3. |
| Day 21–25 | Pregnancy can be confirmed with a relaxin blood test from about day 21. |
| Day 28 (week 4) | Ultrasound can usually detect puppies and heartbeats; the belly may start to show. |
| Day 35 (week 5) | Appetite rises and weight gain becomes obvious; switch to a higher-calorie puppy food if your vet advises it. |
| Day 45 (week 6–7) | X-ray can count the puppies; the whelping box should be ready and nesting often begins. |
| Day 56 (week 8) | Nesting behavior increases; start watching her temperature — a drop below 99°F often means labor within 24 hours. |
| Days 58–68 | Whelping window: most dogs give birth in this period. |
| Day 63 | Expected due date. |
Tips for the wait
Book a vet check early in the pregnancy: a visit around week 4 can confirm it, and an X-ray around day 45 counts the puppies so you know when whelping is done.
Set up the whelping box by week 6 in a quiet, warm spot she already likes — a new box introduced on the due date will not feel safe to her.
From day 56, take her temperature twice a day: a drop below 99°F usually means labor will start within 24 hours.
Keep your vet’s emergency number handy through the whole whelping window, not just on the due date — most dogs whelp a few days early or late.
Do not move the due date because she looks bigger or smaller than expected — belly size depends on litter size, not on how far along she is.
Good to know
Frequently asked questions
How long is a dog pregnant?
About 63 days from ovulation, or 9 weeks. Most dogs whelp between 58 and 68 days after ovulation, so the due date is the middle of a 10-day window, not a fixed day.
Should I count from the mating date or the ovulation date?
Ovulation is more accurate. A mating date works as an estimate, but ovulation can follow mating by a day or two, and sperm can survive several days, so a mating-based date is less exact. If you know the ovulation date from progesterone testing, use that.
Does the breed change the due date?
Barely. Gestation is about 63 days for almost all breeds, large and small. Litter size matters more: very large litters sometimes arrive a day or two early, and single puppies sometimes arrive late. The breed you enter is shown for reference only and does not change the date.
When should I call the vet?
Call your vet if your dog goes past day 68 with no labor, if labor starts but no puppy arrives within 2 hours of strong contractions, if there is green or black discharge before any puppy is born, or if she seems distressed. A vet check and an X-ray around day 45 can confirm the pregnancy and count the puppies.