Cat pregnancy calculator

What this means

Queens are induced ovulators: mating itself triggers the release of eggs, usually within a day or two. That makes the mating date a good anchor, and the remaining spread — 63–65 days typical, 58–72 recorded — is real variation between cats, not a measurement problem.

With several matings, the earliest possible birth counts from the first and the latest from the last, which is why this page asks for both. Kittens born before day 58 are often premature and need help; a birth after day 72 needs a vet.

The milestones are the checkpoints the Merck Veterinary Manual gives, as dates: when a vet can confirm the pregnancy, when an X-ray can count the litter, and when to prepare. Breed, litter size and age offsets that some calculators apply are not sourced and are not used here.

Cat kittening chart for 2026

The expected birth window for a mating on the first day of each month, using the same gestation figures as the calculator (58 to 72 days from mating). For any other date, enter it in the calculator above.

Formula and sources

Sources reviewed 18 September 2026. Each names the figure it supports.

• Dog gestation windows (58–68 days from mating; 62–64 from ovulation), milestones and the whelping temperature drop — Merck Veterinary Manual, "Management of Reproduction: Dogs"
• Cat gestation (63–65 days typical, 58–72 possible), induced ovulation, milestones — Merck Veterinary Manual, "Management of Reproduction: Cats"
• Gestation 63 ± 1 days from ovulation (65 ± 1 from the LH surge) in the bitch — Concannon P. W., "Reproductive cycles of the domestic bitch", Animal Reproduction Science 124(3–4), 2011

This page is an educational estimate, not veterinary advice.

Frequently asked questions