Cat Pregnancy Calculator

How the cat pregnancy calculator works

Cats are induced ovulators: mating triggers the hormone surge that releases eggs, so the mating date is a close stand-in for conception. Veterinary references put birth (queening) at about 64–66 days after that hormone surge, and most owner guides use 63 days from mating as the due date. The calculator adds 63 days to your date and marks a normal window from day 58 to day 70.

To work it out by hand, count nine weeks forward on a calendar from the mating date. For a mating on 1 March 2026, the estimated due date is 3 May 2026.

If you do not know the mating date

Many pregnancies are only noticed when a cat's nipples turn pink or her belly grows. In that case a vet can estimate how far along she is: ultrasound can detect pregnancy from around three weeks, and an X-ray after about day 42–45 shows kitten skeletons and helps count the litter. Use the vet's estimate of days pregnant to back-calculate a mating date.

Cat pregnancy week by week

Signs your cat is pregnant

• Pink, enlarged nipples from about week 3 – one of the earliest reliable signs.
• Gradual belly growth from weeks 4–5 (a swollen belly can also mean illness – have it checked).
• Increased appetite and steady weight gain, often 1–2 kg in total.
• Heat cycles stop.
• More affectionate or, in late pregnancy, more withdrawn and seeking quiet spots.

Home signs are only clues. A vet visit confirms the pregnancy, checks your cat's health and gives a better idea of litter size – most litters are around four kittens, though first-time and older queens often have fewer.

Preparing for the birth

From week 7, put a cardboard box or low-sided basket lined with washable towels in a warm, quiet room. Let her explore it; many cats choose their own spot anyway. Keep clean towels, unscented kitchen paper, a pet-safe heat pad and your vet's out-of-hours number nearby.

Signs of labour and when to call a vet

In the last day or two your cat may become restless, vocal, pant, refuse food and spend time in the nest. Once strong contractions start, a kitten usually arrives within about 30–60 minutes, and kittens commonly follow at intervals of up to an hour.

• Strong straining for 20–30 minutes with no kitten.
• More than two hours between kittens when more are expected.
• Green, black or bloody discharge before the first kitten.
• No kittens by day 70 after mating, or your cat seems weak, feverish or in distress.

Any of these is a reason to call your vet straight away.

Sources

1. Merck Veterinary Manual – Whelping and queening in dogs and cats — merckvetmanual.com
2. Cornell Feline Health Center – Feline reproduction — vet.cornell.edu