Cat Pregnancy Calculator

How long cats are pregnant

Cat gestation runs about 63 to 65 days from a successful mating, with a working range of 60 to 67 days. The VCA Animal Hospitals: pregnancy and parturition in cats page from VCA Animal Hospitals lists the same range and notes that most litters arrive between 63 and 65 days. Cats are induced ovulators, which means a single mating that catches the queen during her fertile window is a tight estimate. Matings spread over several days widen the window because the date of ovulation is not known exactly.

Two milestones matter most for planning:

• Day 21 to 25. Ultrasound can confirm pregnancy. Heartbeats can often be seen by day 28.
• Day 45 or later. Fetal skeletons show up on X-ray, which is the only reliable way to count kittens before birth.

The calculator returns the due date, the realistic window, and the day each milestone lands on. A separate vet visit, not the calendar, is the only way to confirm the pregnancy and the litter size.

Worked example: bred on May 1

Worked example: bred on May 1, 2026

Your queen was bred on May 1, 2026 and the dates were not tracked precisely.

• Estimated due date: July 4, 2026 (May 1 + 64 days)
• Earliest realistic: June 30 (day 60)
• Latest realistic: July 7 (day 67)

Milestones, all counted from the same May 1 start:

• Day 21. May 22. Ultrasound can usually confirm pregnancy.
• Day 28. May 29. Fetal heartbeats are often visible.
• Day 45. June 15. X-ray window opens for counting kittens.
• Day 53. June 23. Kittening box should be set up.
• Day 58. June 28. Start twice-daily temperature checks.
• Day 60. June 30. Earliest realistic queening date.

Week by week development

Week by week: what is happening inside

Feline pregnancy moves faster than canine pregnancy. This table assumes a May 1, 2026 breeding.

Two things surprise first-time breeders. First, the first three weeks are almost invisible, many queens show nothing at all, and a queen that goes off her food for a day or two around day 20 is not necessarily sick. Second, the weight gain in the last two weeks is fast, and a queen can drop her belly visibly in the final ten days.

Signs queening is starting, and when to call the vet

Signs queening (cat labor) is starting, and when to call the vet

Cat labor has three phases, and they differ from dogs in two important ways: stage one can last up to 36 hours, and a long 'pause' of 24 to 36 hours between kittens is considered normal.

• Stage one (up to 36 hours, shorter for experienced queens). Restlessness, panting, pacing, repeated visits to the kittening bed. She may want to be alone or want constant reassurance. Contractions are happening but not visible. Most queens stop eating in the final 24 hours.
• Stage two (delivery). Active straining, the water bag appears, and a kitten is born. Each kitten usually takes 5 to 30 minutes from the start of straining. Mom breaks the sac, clears the mouth and nose, and bites the cord.
• Stage three (placenta). Each placenta follows the kitten, and mom usually eats it.

The single most useful signal is temperature. From day 58, take her rectal temperature twice a day. Normal is 100 to 102.5 F. A drop below 100 F (37.8 C) generally means queening within 12 to 24 hours.

Call a vet right away if: she strains hard for more than 20 minutes without producing a kitten, 10 minutes of straining does not expel a kitten visible at the vulva, she seems depressed or has a fever over 103 F (39.4 C), she loses fresh blood from the vulva for more than 10 minutes, or she has been in active labor for over an hour without progress.

Care changes before the due date

Care changes worth making before the due date

• Food. Switch gradually to a labeled-for-growth or queen-and-kitten food by week 4. The VCA Animal Hospitals: feeding the pregnant cat page covers the food side in detail. By the last third, feed three or four smaller meals a day because the kittens crowd her stomach.
• Kittening box. Set it up by day 53 to 55 so she can get used to it. A cardboard box with a low cut-out entry, lined with newspaper and old towels, in a quiet corner.
• Temperature checks. Start twice-daily rectal checks from day 58 to catch the pre-queening drop.
• Supplies. Clean towels, a scale that reads in grams, a bulb syringe for clearing airways, and your vet's emergency number where you will see it.
• Keep her indoors. A pregnant queen that goes outside can pick up infection, fight, or decide to give birth in a bad spot. Confine her from the last week onward.

Why the due date is an estimate

Why the due date is an estimate, not an appointment

Every date this calculator produces is built from population averages. Real queens do not read the calendar: most litters arrive between 63 and 65 days, but a queen that delivers on day 60 is early and often fine, and one still pregnant on day 67 deserves a vet check. The Merck Veterinary Manual: reproductive management of the female small animal goes over the same day ranges from a clinical angle, and the VCA Animal Hospitals: pregnancy and parturition in cats is the most detailed cat-specific guide.

Two things narrow the estimate if you want a tighter one:

• Ultrasound at day 21 to 25. Confirms the pregnancy and gives the vet a chance to check for resorption or a problem.
• X-ray at day 45 or later. Counts skeletons, which matters enormously once queening starts, because you need to know when the last kitten is out.

Treat the output above as a planning window: when to set up the box, when to start temperature checks, when to clear your calendar. It is a reference estimate, not veterinary advice, and it cannot tell you whether your cat is pregnant or how many kittens are coming. Your veterinarian's examination is the only reliable answer to either question.