Cat Pregnancy calculator

and Week – by- week timeline

Planning kittens? Cat pregnancy typically lasts around 63–65 days, although healthy variation between 60 and 71 days may occur. This breeder-friendly calculator estimates the expected delivery period based on the last observed mating date — a method many breeders prefer when queens mate over several days.

Use the calculator below to estimate important pregnancy dates and follow the week-by-week timeline to understand kitten development, behavioural changes and what to expect throughout pregnancy..

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DAYS 0–2
WEEK 1
Mating &
Ovulation
The queen is in heat and will usually mate repeatedly during this period. Ovulation in cats is induced by mating and typically occurs around 24–48 hours after the last successful mating. Multiple matings over several days increase the likelihood of successful ovulation. Behaviour is often still hormonal at this stage — queens may remain affectionate, vocal, restless or continue calling. At this point there are no visible signs of pregnancy yet.
DAYS 2–4
WEEK 1
Fertilisation
Sperm travel through the reproductive tract toward the oviducts, where fertilisation may occur. The fertilised eggs begin early cell division almost immediately and start their journey toward the uterus. Many queens begin returning to normal behaviour after heat, although some may still briefly show mating behaviour. Pregnancy is still impossible to confirm externally.
DAYS 4–7
WEEK 1
Early Embryo
Development
Embryos continue dividing rapidly while travelling through the oviducts toward the uterus. At this stage they are microscopic and there are still no physical signs of pregnancy. Most queens behave completely normally and appetite is usually unchanged. Internally, however, important developmental processes are already beginning.
DAYS 8–14
WEEK 2
Implantation
The embryos reach the uterus and implant into the uterine wall. Placenta formation begins and will later provide nutrients and oxygen to the developing kittens. Most queens still appear completely normal, although some breeders notice subtle behavioural changes such as increased sleepiness, calmness or appetite changes. Pregnancy still cannot usually be confirmed externally.
DAYS 15–21
WEEK 3
Development
Begins
Major organ systems begin developing and the circulatory system forms. The heartbeat often begins around day 18–20. Some queens start showing the first subtle pregnancy signs — nipples may become slightly pinker (“pinking up”), appetite may increase and behaviour may become calmer. Around this stage, pregnancy may sometimes be detected on ultrasound.
DAYS 22–28
WEEK 4
Rapid Growth
Rapid fetal development continues. The head, limbs, eyes, ears and internal organs are forming. Some queens may experience mild nausea, reduced appetite or become quieter and sleep more. Small, frequent meals are often better tolerated during this stage.
DAYS 29–35
WEEK 5
Pregnancy
Confirmation
This period is often suitable for pregnancy confirmation by ultrasound. Heartbeats may sometimes be visible earlier, but many breeders prefer approximately day 29–35 for clearer confirmation. The abdomen may begin looking fuller, appetite often increases and weight gain may become more noticeable during this period.
DAYS 36–42
WEEK 6
Active
Development
Kittens continue rapid growth. Bones strengthen, muscles develop and facial features become more defined. The queen’s abdomen usually becomes clearly visible. Food intake often increases considerably and many queens sleep more.
DAYS 43–49
WEEK 7
Movement &
Growth
Kittens are growing quickly and fetal movement may become easier to feel, especially when the queen is relaxed. Skeleton mineralisation continues, and kittens may be visible on X-ray from approximately day 42–45. Counting kittens accurately by touch is often difficult.
DAYS 50–56
WEEK 8
Final Growth
Stage
The kittens continue gaining weight and becoming stronger. The queen’s abdomen is usually very visible now, and she may start slowing down, resting more and choosing quiet places. This is a good time to prepare the kittening area and keep daily routines calm and predictable.
DAYS 57–63
WEEK 9
Late Pregnancy
The queen approaches her due date and may become increasingly restless. Many queens seek privacy, spend more time nesting, groom more and prefer smaller meals due to reduced abdominal space. Kitten movement is often very noticeable during this stage.
DAYS 64–66
WEEK 10
Expected Delivery
Window
Most queens give birth during this period when counting from the last day of mating, although healthy variation is completely normal. Watch for nesting behaviour, contractions, milk production, temperature drop and behavioural changes. Some queens may deliver slightly earlier or later without concern.
DAYS 67–70+
BEYOND
Extended Pregnancy
Some healthy queens naturally carry slightly longer, especially if ovulation occurred later than expected. First-time mothers may also occasionally go longer. If labour has not started by day 69–70 or the queen seems unwell, veterinary advice is recommended.
Please remember: every queen is different. Pregnancy length, visible signs and behavior may vary depending on litter size, breed, age and individual hormonal patterns.

FAQ

Most cat pregnancies last around 63–65 days, although healthy variation between 58 and 70 days may occur. Timing depends on ovulation, litter size and individual differences between queens. For breeders, pregnancy is often counted from the last observed mating date, especially when queens mate over several days.

Pregnancy may often be confirmed by ultrasound around day 26–30, although heartbeats may sometimes be visible earlier. Experienced veterinarians may occasionally confirm pregnancy by gentle abdominal palpation from around day 28 onwards, though accuracy depends on the queen and litter size.

Many queens begin showing “pinking up” around week 3, usually between days 16–24. The nipples may become pinker, slightly enlarged and more noticeable, although not every queen shows obvious changes.

Kitten movement may sometimes be felt from approximately days 40–50, especially in slimmer queens or smaller litters. Movement becomes easier to notice later in pregnancy, although some queens hide it surprisingly well.

Ultrasound may confirm pregnancy from around day 21–30, depending on equipment and timing. X-ray is usually more useful from around day 42–45, when skeleton mineralization begins and kittens become visible.

Yes — especially during weeks 3–4, some queens experience mild nausea or temporary appetite changes. Later in pregnancy, appetite usually increases significantly, although queens near delivery may again prefer smaller, more frequent meals.

Common signs include:

• nesting behaviour
• restlessness
• increased grooming
• seeking privacy
• reduced appetite
• milk production
• contractions or panting

Many queens become noticeably clingier — or, alternatively, prefer complete privacy.

Contact a veterinarian if:

• the queen appears unwell or distressed
• there is abnormal discharge
• strong contractions continue without kittens being born
• pregnancy continues significantly beyond the expected time frame
• you are concerned something feels “not quite right”

Breeders know their queens best — if behaviour feels unusual, it is always reasonable to ask for veterinary advice.

Yes. Healthy pregnancies may naturally continue beyond day 65, especially if ovulation occurred later than expected or mating happened across several days. Some queens deliver around days 67–70 and still have perfectly healthy litters. Timing should always be interpreted together with the queen’s condition and behaviour.