Cat Heat Cycle Calculator
When will your cat be in heat again? This free cat heat cycle calculator takes the date her last heat started and estimates her next heat and when this one should end, shows where she is in the cycle today, explains the stages of the feline estrus cycle, finds the best out-of-heat window to plan a spay, and tells you when a kitten’s first heat is due and how often cats cycle.
How the Cat Heat Cycle Calculator Works
The five tools cover the next heat, where she is now, the cycle stages, the best spay-timing window, and a kitten’s first heat and frequency.
How Long Does a Cat Stay in Heat, and How Often?
Active heat lasts about a week on average (5 to 7 days), though it can be as short as a day or run up to around three weeks. If she is not bred, she drops out of heat for roughly 1 to 3 weeks and then cycles straight back in — which is why owners often describe a cat as being in heat “every couple of weeks.” Unlike dogs, cats do not bleed during heat; the signs are behavioural.
| Measure | Typical | Range |
|---|---|---|
| Length of each heat | 5–7 days | 1–21 days |
| Gap between heats (unbred) | ~1–3 weeks | 2–20 days out of heat |
| Heat-to-heat cycle | ~2–3 weeks | 14–21 days |
| First heat (puberty) | 4–6 months | As early as 3–4 months |
| Breeding season | Spring–autumn (outdoor) | Year-round (indoor light) |
The Stages of the Feline Heat Cycle
Vets describe the feline estrous cycle in distinct phases. Knowing them makes the behaviour far less confusing.
| Stage | Duration | What happens |
|---|---|---|
| Proestrus | 1–2 days | Hormones rise; toms take interest but she is not yet receptive. |
| Estrus (heat) | 5–7 days (1–21) | The receptive phase: yowling, rolling, rubbing, raised hindquarters. |
| Interestrus | ~1–3 weeks | The rest between heats if she was not mated; normal behaviour returns. |
| Diestrus / Metestrus | 30–40 days | After mating triggers ovulation; if she conceives, pregnancy is ~63 days. |
| Anestrus | Winter months | Seasonal off-switch in short daylight; no heats until spring. |
Signs Your Cat Is in Heat
The signs of heat are behavioural and can be dramatic. The classic ones are loud, persistent yowling or crying, excessive rubbing against furniture, people and objects, rolling on the floor, and adopting the mating posture — chest down, hindquarters raised and tail to one side — especially if you stroke her lower back. Many cats become unusually affectionate or restless, may go off their food, and will try hard to escape outdoors to find a mate. Some queens show a “silent heat” with few obvious signs. None of this involves bleeding; visible blood is not normal in a cat in heat and warrants a vet visit.
Planning a Spay Around the Cycle
If you’re booking a spay, many vets prefer to operate when a cat is out of active heat, because the reproductive tract is less engorged and the surgery is simpler. That calmer window usually falls after a heat ends and before the next one begins — the Spay Timing tab maps it to your dates. That said, plenty of clinics will spay a cat in heat when needed, and because queens cycle so frequently, waiting for the “perfect” window often just means another noisy heat and more risk of an accidental litter. Spaying is the only permanent way to end the cycle, and it also removes the risk of pyometra (a serious uterine infection) and reduces mammary-cancer risk when done early. The right timing is a conversation with your veterinarian.
Frequently Asked Questions
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