Cat Heat Cycle Calculator
This cat heat cycle calculator predicts your cat's next heat and estrus duration. Enter the date her last heat cycle started to get instant estimates — useful for both breeding management and unwanted-pregnancy prevention.
Quick Answer
Cat heat lasts 4–10 days per cycle. If not mated, an unspayed cat returns to heat approximately every 2–3 weeks. Enter the date your cat's last heat started above to estimate her next cycle.
Cat Heat Cycle Calculator
Free tool — no signup required
Enter the first day you noticed signs of heat (vocalizing, rolling, affectionate behavior).
Cat Heat Cycle Stages
- Proestrus (1–2 days): mild early signs; not yet receptive to mating.
- Estrus (4–10 days): full receptivity — the loud vocalizing, rolling, and mating posture most owners associate with a cat “in heat.”
- Interestrus (2–3 weeks): the resting period between cycles if the cat wasn't mated — she'll cycle back into heat after this window.
- Anestrus (winter months): a longer seasonal rest period when cycling stops entirely, typically triggered by shorter daylight hours in temperate climates.
Signs of a Cat in Heat
- Loud, persistent vocalizing (yowling) — often the first and most disruptive sign.
- Rolling and rubbing against furniture and people more than usual.
- Mating posture (lordosis): crouching low with the rear raised when petted near the tail base.
- Frequent urination or spraying.
- Escape attempts to get outside and find a mate.
Induced Ovulation Explained
Cats are induced ovulators — unlike dogs and humans, a female cat doesn't release eggs on a fixed internal schedule. Ovulation is triggered by the physical act of mating. Without that trigger, she never ovulates and simply cycles back into heat repeatedly throughout the breeding season, rather than resolving into either pregnancy or a long hormonal rest period the way a dog does after each cycle.
Preventing Unwanted Pregnancy & Spaying Recommendation
Keeping an unspayed cat strictly indoors and away from unneutered males prevents pregnancy but does not stop the cycling itself — she'll keep coming into heat every few weeks until spayed, mated, or the breeding season ends.
Most vets recommend spaying between 4 and 6 months, ideally before the first heat — spaying before the first cycle is linked to the lowest lifetime risk of mammary tumors.
Cat vs. Dog Heat Cycle
| Species | Cycle Length (Active) | Frequency If Unmated |
|---|---|---|
| Cat | 4–10 days | Every 2–3 weeks |
| Dog | 18–21 days | Every ~6 months |
See our dog heat cycle calculator for the canine equivalent, or our cat gestation calculator if your cat has already been bred.
Frequently Asked Questions
Sources & References
- Merck Veterinary Manual — Feline reproduction and the estrous cycle
- Cornell Feline Health Center — Feline reproductive health
GestationCalc Editorial Team
Our editorial team includes animal husbandry specialists, veterinary consultants, and agricultural extension educators. Content is reviewed against peer-reviewed research and guidance from USDA, Penn State Extension, and the Merck Veterinary Manual.
Last reviewed: September 1, 2026