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
How long does cat heat last?
A single cat heat cycle (estrus) lasts approximately 4 to 10 days if the cat is not mated. If she isn't bred during this window, she'll typically cycle out and then back into heat within 2–3 weeks, rather than settling into a long rest period the way dogs do.
How often do cats go into heat?
An unmated queen returns to heat roughly every 2 to 3 weeks throughout the breeding season, since cats are induced ovulators and don't get the hormonal 'reset' of ovulation unless they actually mate.
What are the stages of the cat heat cycle?
Proestrus (1–2 days, mild early signs), estrus (4–10 days, full receptivity and the classic vocalizing/rolling behavior), interestrus (2–3 weeks between cycles if unmated), and anestrus (a longer resting period, typically during winter months when daylight is short, when cycling stops entirely).
What are the signs a cat is in heat?
Loud, persistent vocalizing (yowling), rolling on the floor and increased affection, assuming a mating posture (crouching low with the rear raised) when petted near the tail base, frequent urination or spraying, and a strong drive to escape outside to find a mate.
What is induced ovulation in cats?
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 will simply cycle back into heat repeatedly rather than resolving into pregnancy or a long rest period.
How do I prevent an unwanted cat pregnancy?
Keep an unspayed cat strictly indoors and away from unneutered males during heat — this prevents pregnancy but does not stop the cycling itself. Spaying is the only way to permanently stop both the heat cycle and the risk of pregnancy.
When should I spay my cat?
Most veterinarians recommend spaying between 4 and 6 months of age, ideally before the first heat cycle, since spaying before the first heat is linked to the lowest lifetime risk of mammary tumors. Some cats can cycle as early as 4 months, so earlier spaying (some clinics offer it from 8 weeks) is increasingly common.
How does the cat heat cycle compare to the dog heat cycle?
Cats cycle far more frequently than dogs when unmated — every 2–3 weeks compared to roughly every 6 months for dogs — because cats are induced ovulators while dogs are spontaneous ovulators. See our dog heat cycle calculator for the canine comparison.
Sources & References
- Merck Veterinary Manual — Feline reproduction and the estrous cycle
- Cornell Feline Health Center — Feline reproductive health
Kanika
Researched and reviewed by Kanika, founder of GestationCalc. All gestation data is verified against primary veterinary and agricultural sources before publication.
Last reviewed: September 1, 2026