Once you know the mating date you can work out when to have the whelping or queening box ready. Pick the species, enter the mating date, and this calculator shows the expected delivery window, the date based on average gestation length, how many days have passed since mating, and how long until the window opens.
The figures used are 58 to 68 days after mating for dogs with an average of 63 days, and 61 to 65 days for cats with an average of 63 to 65 days. The 63 day average is reported from ovulation, so a calculation from the mating date alone carries a wider window. Breeding management and attending the delivery are judged case by case by your veterinarian, following AAHA and American Association of Feline Practitioners (AAFP) guidance. Guidance current as of October 2026.
This tool only does date arithmetic. It does not estimate litter size, delivery difficulty or the need for a cesarean, and it is not a substitute for ultrasound or temperature records. Weaning timing belongs to a separate tool that works from the birth date. This tool is for reference only and does not replace veterinary care. Contact your veterinarian right away if you notice symptoms or suspect a problem.
Frequently Asked Questions
Dogs are reported to deliver 58 to 68 days after mating and cats 61 to 65 days. Pinning it to a single day would be off by that much, so the tool shows the window together with the average based date.
The first mating date gives the widest window and the last one gives the latest. Enter each date in turn and treat the two windows combined as the whole period to be ready for.
If the window has passed with no sign of labor, or labor has started and is dragging on, contact your veterinarian or an emergency animal hospital without waiting.