Dog Pregnancy Calculator
Choose the actual date basis. First mating uses an illustrative 65-day midpoint within a broad 58–72-day window; ovulation uses 63 days with a 62–64-day window; LH surge / initial progesterone rise uses 65 days with 64–66.
Formula and sources updated · Data sources · 2View algorithm, constants and default inputs (JSON)
Results
About this calculator
Choose the actual date basis. First mating uses an illustrative 65-day midpoint within a broad 58–72-day window; ovulation uses 63 days with a 62–64-day window; LH surge / initial progesterone rise uses 65 days with 64–66.
Worked example
calculated with the default values below
Date for the selected dating basis 2026-10-31 · Gestation length 63 days · Reference date 2026-10-31 · Dating method Custom Estimated due date 2027-01-02 · Earliest possible 2026-12-28 · Latest likely 2027-01-11 · Days since mating 0 days · Days remaining 63 days
Method and assumptions
Choose the actual date basis. First mating uses an illustrative 65-day midpoint within a broad 58–72-day window; ovulation uses 63 days with a 62–64-day window; LH surge / initial progesterone rise uses 65 days with 64–66. A custom day count retains the broad mating window and is not a hormone-based prediction. The reference date affects elapsed/remaining days only. These estimates cannot diagnose pregnancy or predict labor; ask a veterinarian.
Data sources
The references explain definitions and methods; any extra preset must be checked against the assumptions on this page.
Disclaimer
These calculators offer general guidance and do not replace veterinary advice. Individual animals vary with breed, weight, health status and medication. Suspected poisoning from chocolate, medication, plants or chemicals is an emergency — contact your veterinarian or a pet poison control service immediately rather than relying on a calculator.
Implementation source
This record describes the implementation used by this page. It is not independent validation. External references, when available, support only the stated formula or definition; estimates and custom rules retain their own assumptions.
Formula and variables
estimate = reference event + selected days; mating window = +58..72 d; ovulation = +62..64 d; LH / initial progesterone rise = +64..66 d
The reference date affects elapsed/remaining days only. These estimates cannot diagnose pregnancy or predict labor; ask a veterinarian.
Frequently asked questions
What should I know about this estimate?
Choose the actual date basis. First mating uses an illustrative 65-day midpoint within a broad 58–72-day window; ovulation uses 63 days with a 62–64-day window; LH surge / initial progesterone rise uses 65 days with 64–66. A custom day count retains the broad mating window and is not a hormone-based prediction. The reference date affects elapsed/remaining days only. These estimates cannot diagnose pregnancy or predict labor; ask a veterinarian.