Animal Gestation Calculator

Use this calculator to estimate the expected due date for a pregnancy in a common domestic or livestock animal. Select the species and enter the breeding date or last known mating date. The calculator adds a typical gestation length for that species and compares the result with today's date.

The estimate uses the following typical gestation lengths: cat 64 days, dog 63 days, cow 283 days, goat 150 days, guinea pig 68 days, horse 340 days, llama 350 days, rabbit 31 days, sheep 147 days, and pig 114 days.

These are typical average values, not exact pregnancy durations. Gestation can vary with the individual animal, breed, health, pregnancy conditions, and the accuracy of the breeding or mating date. Use the calculated due date as a planning reference rather than a precise prediction or veterinary diagnosis.

Species: Select the animal. The calculator uses a species-specific typical gestation length.

Breeding date: Enter the date of breeding, mating, or the last known mating. The estimated due date is calculated by adding the typical gestation length to this date.

Typical gestation (days): The typical number of days used for the selected species.

Estimated due date: The expected due date based on the entered breeding date and the typical gestation length.

Days remaining: The number of days from today until the estimated due date. It is shown as 0 once the estimated due date has been reached or passed.

Days overdue: The number of days that have passed since the estimated due date. It is shown as 0 before the estimated due date.

Progress (%): The estimated percentage of the typical gestation period that has elapsed, capped at 0% before breeding and 100% on or after the estimated due date.

If the animal shows signs of labor, illness, distress, an unusually long pregnancy, or other concerns, consult a veterinarian rather than relying on a calendar estimate.