About the Cat Pregnancy Calculator
This cat pregnancy calculator estimates when your queen is due to give birth from the date she mated. It returns an estimated due date 65 days after mating, the usual delivery window of about 61 to 72 days, how many days and weeks pregnant she is on the date you choose, the current stage of pregnancy and a dated timeline of milestones such as pinking up, ultrasound, X-ray and when to set up a nesting box.
It is meant for breeders planning a litter, owners whose unspayed cat got outdoors, and rescuers looking after a pregnant stray. Knowing the window lets you book vet checks at the right time, adjust her diet in the final third and make sure someone is around when the kittens arrive.
Cats are induced ovulators: mating triggers the hormone (LH) surge that releases eggs, and the Merck Veterinary Manual puts birth at 64–66 days after that surge. Because queens are often mated several times over two or three days, and the exact date is often unknown, treat the due date as an estimate. If you only know roughly when she was out, use the earliest possible date and ask your vet to estimate gestational age by ultrasound.
How to use the cat pregnancy calculator
- 1Enter the date your cat mated (the first date if there were several).
- 2Enter today’s date to see how far along she is.
- 3Read the estimated due date and the 61–72 day window.
- 4Use the timeline to book an ultrasound and plan diet changes.
- 5Set up a nesting box about a week before the window opens.
Formula and method
Cats ovulate in response to mating, so the mating date is close to the hormone surge that starts the pregnancy clock. The Merck Veterinary Manual gives birth at 64–66 days after that LH surge, so the calculator uses the midpoint, 65 days, for the due date. Most queens deliver between roughly 61 and 72 days after mating; kittens born well before that are often premature, and a queen still pregnant after 72 days should be checked by a vet.
Days pregnant is the number of days between the mating date and the check date, and weeks pregnant is that number divided by 7. Milestones (implantation around day 14, pinking up around days 15–21, palpation around days 17–25, ultrasound at days 25–35 and skeletons visible on X-ray from about days 42–45) are typical ranges, not exact dates.
- 65
- Estimated gestation in days (midpoint of 64–66 days after the LH surge)
- 61–72
- Usual range of delivery, in days after mating
Worked examples
Mated on 1 September 2026
Adding 65 days to 1 September gives 5 November 2026. On 15 October she is on day 44 (about 6.3 weeks) with 21 days to go, and kittens would usually arrive between 1 November (day 61) and 12 November (day 72).
Checking in the final days
A mating on 10 December 2026 gives a due date of 13 February 2027. On 8 February she is on day 60, five days before the estimate, so the nesting box should already be in place.
Early pregnancy: pinking up
Fifteen days after a 20 June mating, her nipples may be starting to pink up. The estimated due date is 24 August, 50 days away, and an ultrasound from about day 25 can confirm the pregnancy.
Frequently asked questions
How long are cats pregnant?+
About 63–65 days, or roughly nine weeks. The Merck Veterinary Manual puts birth at 64–66 days after the hormone surge triggered by mating, and most queens deliver between about 61 and 72 days after mating.
How can I tell if my cat is pregnant?+
Around days 15–21 her nipples usually become pinker and larger (“pinking up”). A vet can often feel the kittens at about days 17–25, confirm the pregnancy by ultrasound from about day 25 and count kittens on an X-ray once skeletons show, from about days 42–45.
What are the signs my cat is about to give birth?+
In the last day or two she may search for a hiding place, nest, stop eating, become restless or very affectionate, and groom her belly and genitals. Active labour brings visible contractions, and the first kitten usually follows within about an hour of strong straining.
When should I call the vet during birth?+
Call if she strains hard for 20–30 minutes without producing a kitten, if more than about 2 hours pass between kittens with straining, if there is a foul or very bloody discharge, or if she is still pregnant after day 72.
How many kittens do cats usually have?+
Most litters have about 4 kittens, with a common range of 1 to 8 or more. First litters and very young or older queens tend to be smaller. An X-ray late in pregnancy gives the most reliable count.
This tool gives general estimates and is not medical advice. Talk to a doctor or qualified professional about your health, diet or training.