Dog Pregnancy Calculator
Estimate when a dog will whelp from the breeding date, LH surge or first day of diestrus, with the range from the Merck Veterinary Manual.
Earliest expected due date
Thursday, December 24, 2026
- Latest expected due date
- Thursday, January 7, 2027
Counting from the first breeding the female allowed, normal gestation is 58 to 72 days. The earliest expected due date is Thursday, December 24, and the latest is January 7, 2027. Your veterinarian can confirm the timing.
Calculation breakdown
| Step | Formula | Result |
|---|---|---|
| Shortest normal gestation | 58 to 72 days from the first breeding the female allowed | 58 days |
| Longest normal gestation | 58 to 72 days from the first breeding the female allowed | 72 days |
How it works
Choose how you are counting and enter the date. The calculator shows the earliest and latest expected due dates.
Worked example
Counting from the LH surge on 26 October 2026:
- Earliest: 26 October + 64 days = 29 December 2026
- Latest: 26 October + 66 days = 31 December 2026
Rounding
Dates are whole days. The range already allows for normal differences between dogs.
Sources
Frequently asked questions
How long is a dog pregnant?
The Merck Veterinary Manual gives normal gestation as 56 to 58 days from the first day of diestrus, 64 to 66 days from the initial rise in progesterone or the LH surge, or 58 to 72 days from the first time the female permitted breeding.
Why are there three different ways to count?
Breeding can happen on several days around ovulation, so counting from the first breeding gives a wide window of 14 days. Hormone tests and the start of diestrus pin down the timing, so the windows are only 2 or 3 days. The calculator lets you choose the one you have.
How do I know which date to use?
If you do not have hormone test results, use the first date the female permitted breeding. A veterinarian can measure progesterone or the LH surge, or find the start of diestrus from cell tests, and then the narrower ranges apply.
When should I see a veterinarian?
See a veterinarian early to confirm the pregnancy, plan her care and know what to expect at whelping. The calculator is an estimate for planning, and your veterinarian can confirm the dates and tell you when something is wrong.
Does the due date change with breed or litter size?
The ranges here are the general ones from the manual. Individual dogs can differ, so ask your veterinarian about your dog. Call a veterinarian promptly if she is overdue or shows signs of trouble.
For information only, not veterinary advice. Ask a veterinarian to confirm the pregnancy, the due date and your dog's care.