Updated
Cat pregnancy calculator
Cats ovulate because they mated, so the mating date is the one date that matters — and the honest answer is a window: 63–65 days is typical, 58–72 possible. Milestones and the "call the vet" date are worked out as dates, not day numbers you have to count.
4 November 2026 expected due date
Window 29 October 2026 to 12 November 2026. From mating on 1 September 2026: 58–72 days, 64 expected.
- Earliest
- 29 October 2026
- Typical (63–65 days)
- 3 November 2026 to 5 November 2026
- Latest
- 12 November 2026
- Day 21 — 22 September 2026
- "Pinking up" of the nipples from about day 21; ultrasound from about day 21–25
- Day 42 — 13 October 2026
- X-ray can count kittens from about day 42
- Day 60 — 31 October 2026
- Prepare a quiet nesting box; labour can begin from day 60
- Day 70 — 10 November 2026
- No kittens by this day (day 70 from the last mating): call the vet
- During labour
- Call the vet for 30 minutes of hard straining without a kitten, or more than 4 hours between kittens with more expected.
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.
When to see a vet
- No kittens by day 70 from the last mating: call.
- Thirty minutes of hard straining without a kitten, or more than four hours between kittens when more are expected.
- Any bleeding, foul discharge, collapse or a queen that stops eating for more than a day late in pregnancy.
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
When is my cat due?
About 64 days after mating, with 63–65 typical and 58–72 possible: enter the mating date above and the page gives the window as dates.
Why does the cat calculator not ask for an ovulation date?
Because cats ovulate as a result of mating (induced ovulation), usually within a day or two of it, there is no separate ovulation date to enter. The mating date is the anchor; with several matings, enter the first and the last.
How can I tell my cat is pregnant?
The nipples "pink up" and enlarge from about day 21; a vet can confirm by ultrasound from about day 21–25 and can count kittens on an X-ray from about day 42, when the skeletons have mineralised. The page gives those days as dates.
When should I call the vet during a cat pregnancy?
No kittens by day 70 from the last mating; 30 minutes of hard straining without a kitten; more than 4 hours between kittens when more are expected; or any bleeding, foul discharge or collapse.