Using the gestation calculator

Use the gestation calculator when you need planning dates without saving a breeding record. It provides an estimate, not a diagnosis.

Calculate from what you know

1. Open Gestation Calculators and choose the species. From an active breeding cycle, you can also choose Open gestation calculator when available.
2. Choose Exact Breeding Date when you know the breeding, insemination, or transfer date.
3. Choose Exposure Window when you only know the first and last day of exposure.
4. Enter the date or window and choose Calculate.

A wider exposure window produces a wider likely birth window because conception could have happened on more than one day. Use the dates that actually happened; do not narrow the range just to get a more precise-looking answer.

Some species offer additional options, such as breed, fetal sex, or whether this is a first pregnancy. Leave an optional answer unchanged when you do not know it.

Use the result

The result shows the best expected date, a likely window, and a care timeline. Use the timeline to plan checks and preparation, while following your veterinarian's advice for the individual animal.

Choose Copy results to share the estimate, Print for a paper copy, or Add to calendar to put the dates in your calendar. These actions do not create a breeding cycle.

When signed in, choose Log in breeding records to open a record with the dates carried over. Choose the mother and review the details before saving. The calculator itself does not save a cycle. See Recording a breeding for the remaining steps.

If you are already tracking this pregnancy, use Adjust projection on that cycle rather than creating a duplicate.

If Calculate does not produce a result, check that the required date is present and that an exposure window ends on or after it starts.

The calculator cannot assess an individual animal's health or veterinary findings. If the dates seem wrong, check the species, starting dates, and optional answers. Follow your veterinarian's guidance for the individual animal.

Updated on: 03/09/2026