Cat Pregnancy Calculator
Enter the date your cat mated to calculate her estimated due date and a safe birth window. The calculator also maps out every key milestone across all nine weeks of pregnancy, from the first nipple changes to nesting behavior and the final temperature drop that signals labor is near. Results update instantly as you type.
How long is a cat pregnant?
A cat's pregnancy (called the gestation period) lasts an average of 63 days from the date of mating, though a healthy range is 58 to 72 days. In weeks, that works out to roughly nine weeks. Individual cats, litter size, and breed can all cause variation: Siamese cats tend toward longer pregnancies, while very large litters sometimes arrive a day or two early. Premature kittens born before day 58 typically have underdeveloped lungs and face poor survival odds without specialist neonatal care. If your cat passes day 72 with no sign of labor, call your vet immediately.
Week-by-week cat pregnancy signs
Weeks 1-2 are silent: fertilized eggs travel to the uterus and implant with no outward sign. The first clue most owners notice comes at days 15-18, when the nipples enlarge and turn a brighter pink color, a change breeders call "pinking up." By week 3, mild morning sickness may cause brief vomiting, and the embryos are large enough for a vet to feel by gentle palpation. From week 4 the belly visibly rounds, appetite increases, and a veterinary ultrasound can count embryos with reasonable accuracy. Week 5 sees rapid fetal growth: your cat may gain 1-2 lb over the whole pregnancy and her food intake should increase by 25-50 percent above her pre-pregnancy baseline. By week 7 the kittens are large enough to count on an x-ray. In the final week (week 9), your cat will seek out a nesting spot, her appetite may dip, and her rectal temperature will drop below 99 F (37.2 C) within 24 hours of labor starting.
Nutrition and care during pregnancy
Switch your queen to a high-quality kitten food at around weeks 4-5. Kitten food is calorie-dense and higher in protein and calcium, matching the demands of growing kittens inside the womb and later milk production. Feed small meals three to four times a day rather than one large bowl, especially as the litter takes up more abdominal space and reduces stomach capacity. Do not supplement calcium without veterinary guidance: excess calcium during pregnancy can paradoxically increase the risk of eclampsia (milk fever) after birth. Keep fresh water available at all times and avoid unnecessary stress, long car journeys, and contact with unfamiliar cats during the third trimester.
Preparing for birth and recognizing labor
Set up a nesting box in a quiet, warm, low-traffic room around week 8. A cardboard box with low sides (so the queen can exit easily) lined with clean towels works well. In the 24-48 hours before active labor you may notice: reduced appetite, increased restlessness and vocalization, grooming of the belly, and a rectal temperature drop below 99 F (37.2 C). Stage 1 labor (early contractions) lasts 6-36 hours and involves visible restlessness and nesting. Stage 2 is active delivery: kittens typically arrive 10-60 minutes apart. Stage 3 is placenta delivery, which should follow each kitten. Call your vet immediately if: strong contractions last more than 30 minutes without a kitten, more than 2 hours pass between kittens, green or black discharge appears before the first kitten, or your cat shows signs of extreme distress or exhaustion.
Cat gestation stages at a glance
| Day | Milestone | Action needed |
|---|---|---|
| Day 1 | Mating | Record the date precisely |
| Day 15-18 | Nipple "pinking up" | First visible sign of pregnancy |
| Day 21 | Possible morning sickness | Offer small, frequent meals |
| Day 25-30 | Ultrasound confirms pregnancy | Book vet appointment |
| Day 28-35 | Switch to kitten food | Higher calorie and protein needs begin |
| Day 30 | Belly visibly larger | Avoid rough handling of abdomen |
| Day 45+ | X-ray for kitten count | Know how many kittens to expect |
| Day 56 | Nesting behavior starts | Provide a quiet nesting box |
| Day 60 | Temperature drop below 99 F | Labor within 24 hours |
| Day 63 | Average due date | Monitor closely; labor imminent |
| Day 72 | Latest safe birth | Emergency vet if no delivery by now |
Key milestones during a typical 63-day feline pregnancy.
Frequently asked questions
How accurate is this cat pregnancy calculator?
The due date is an estimate based on the assumption that fertilization occurred close to the mating date and that gestation follows the average of 63 days. In reality, cats can remain fertile for several days after mating and gestation varies between 58 and 72 days. Treat the calculated date as the center of a 2-week window rather than a fixed deadline. A veterinary ultrasound from day 25 and an x-ray from day 45 will give you a much tighter estimate.
What is "pinking up" in cats?
Pinking up refers to the visible change in the nipples that typically occurs 15-18 days after mating. The nipples swell and turn a more vivid pink color due to increased blood flow and early hormonal changes. It is usually the first sign owners notice, especially in cats that have not been pregnant before, because the change is dramatic compared with the flat, pale nipples of a nulliparous (never-pregnant) queen.
Can a cat be pregnant for less than 58 days?
Technically yes, but kittens born before day 58 are considered premature and have very low survival rates because their lungs are not fully developed. If your cat appears to go into labor before day 58, contact your vet immediately rather than waiting.
My cat mated with multiple toms. Which date should I use?
Use the date of the first observed mating for the earliest possible due date estimate. Because cats can be fertilized on multiple days of their heat cycle and can carry kittens from different fathers in the same litter (a phenomenon called superfecundation), the exact conception date is uncertain. A veterinary ultrasound is the most reliable way to estimate gestational age when the mating history is unclear.
How many kittens can I expect?
Average litter size is 4-6 kittens, but litters can range from 1 to 9 or more. Litter size tends to increase with each pregnancy up to about the fourth or fifth litter and declines again in older cats. An x-ray after day 45 is the most accurate way to count kittens before birth, which helps you know when the labor is complete.
When should I take my pregnant cat to the vet?
The first visit should be around day 25-30 for ultrasound confirmation of pregnancy. A second visit around week 6-7 for a health check and an x-ray to count kittens is advisable. In the final week, have your vet's emergency number on hand and call at once if labor lasts more than 2 hours between kittens, you see green discharge before any kitten is born, or your cat shows extreme distress.