Calculate your cat's due date, trimester milestones, and pregnancy progress
If your cat has mated and you suspect she may be pregnant, one of the first things you will want to know is when the kittens are due. Cat pregnancy (also called the gestation period) typically lasts between 63 and 67 days, with an average of 65 days from the date of mating. That is approximately 9 weeks, making cat pregnancies considerably shorter than human pregnancies. Understanding the timeline of your cat's pregnancy helps you prepare for the arrival of kittens, schedule veterinary check-ups at the right times, and recognise when something might not be progressing normally. This calculator takes the mating date and computes the expected due date, the earliest and latest likely delivery dates, and the key trimester milestones. Cat pregnancy is divided into three trimesters of roughly three weeks each. Each trimester brings distinct developmental changes, and knowing which stage your cat is in helps you provide the right nutrition, environment, and care. The RSPCA recommends a veterinary check-up early in pregnancy to confirm the pregnancy and discuss any breed-specific considerations.
To calculate your cat's due date and pregnancy timeline: 1. Enter the date of mating. If you are unsure of the exact date but know the approximate window, use the earliest likely mating date for a conservative estimate. 2. The calculator instantly shows the expected due date (65 days from mating), plus the earliest (63 days) and latest (67 days) delivery dates. 3. Review the trimester milestones to understand which developmental stage your cat is currently in. 4. Check the "days pregnant" and "weeks pregnant" counters to track progress. 5. If your cat has not delivered by day 70, contact your vet for advice. Prolonged pregnancy can indicate complications that need professional attention.
The cat gestation calculator uses the following established veterinary timelines: Average gestation: 65 days from mating Normal range: 63 to 67 days Earliest due date = Mating date + 63 days Expected due date = Mating date + 65 days Latest due date = Mating date + 67 days Trimester milestones: - First trimester ends: Mating date + 21 days (days 1-21) - Second trimester ends: Mating date + 42 days (days 22-42) - Third trimester: Days 43 to birth Current pregnancy progress: - Days pregnant = Today - Mating date - Weeks pregnant = Days pregnant / 7 (rounded down) - Current trimester: First (days 0-21), Second (days 22-42), Third (day 43+) These timelines are based on veterinary obstetric references and are consistent with guidance from the RSPCA and International Cat Care.
Inputs: Mating date: 1 January 2026.
Inputs: Mating date: 15 days ago.
Inputs: Mating date: 38 days ago.