
Many cat owners want to know: “How long are cats in heat?” A female cat in heat, also called “in season” or “in estrus,” is fertile and can get pregnant. This period usually lasts between four and seven days. However, the whole cycle, including periods when she is not fertile, can last from one to six weeks. During this time, you may notice various changes in her behavior, as she is showing male cats she is ready to mate. Knowing about the heat cycle is important, especially if you don’t want your home filled with kittens.

What Does It Mean When a Cat Is in Heat?
When a female cat is in heat, her body goes through hormone changes to get ready for pregnancy. Unlike humans, cats do not have periods in the same way. Instead of shedding the lining of their uterus, it is absorbed by their body, so it’s rare to see any real bleeding. If you do see a lot of blood, you should call your vet right away, as this could be a sign of illness, like a urinary infection.
The main signs that a cat is in heat are changes in her behavior. She may become much louder than usual, crying, meowing, or yowling, which is often called “calling.” She might also become much more friendly, rubbing against you, furniture, or anything nearby. This is a way for her to spread her scent and attract male cats. Other signs include rolling on the floor, arching her back, crouching low, or moving her tail to the side when touched. Some cats might urinate more often or spray urine as a way to mark territory and signal their fertility to males. These behaviors can be tough to handle, but they are normal and usually not painful for your cat. If you think your cat is in pain, you should visit your vet.

Understanding the Estrous Cycle in Cats
The estrous cycle is a cat’s reproductive cycle. Cats are “seasonally polyestrous,” which means they go into heat several times during a certain period of the year, mostly influenced by daylight and temperature. In the Northern Hemisphere, cats usually breed from February to October. More daylight hours trigger cats to start cycling.
The cat’s reproductive cycle has five stages:
- Proestrus: Lasts 12 hours to 3 days; the cat starts acting differently to attract males but isn’t ready to mate yet.
- Estrus: This is when the cat is in heat and is ready to mate.
- Interestrus: Lasts 1-3 weeks of rest if the cat doesn’t mate and get pregnant, before the next heat.
- Diestrus: If the cat becomes pregnant, this is the pregnancy stage, which lasts 61 to 72 days.
- Anestrus: The non-breeding part of the year, usually in late fall and winter, though this may not apply to indoor cats.

Indoor cats can go into heat any time of year if they are exposed to artificial light and kept in comfortable temperatures.
How Long Are Cats in Heat?
There isn’t one exact answer, as it depends on whether the cat mates and other factors. However, some general timeframes can help you understand what to expect.
Length of Each Heat Cycle
The heat (estrus) phase usually lasts about six to seven days, but it can be as short as one day or as long as 21 days. Breeding often shortens this period because cats ovulate only when they mate. After mating, a cat often exits heat within a day or two. If she does not mate, the heat can last a little longer-sometimes up to 10 days-before going into a short period of rest. Then, the cycle can repeat.

Stage | Length | Description |
---|---|---|
Proestrus | 12 hours – 3 days | Shows interest but not ready to mate |
Estrus (Heat) | 1 – 21 days (average 6-7 days) | Fertile and receptive to males |
Interestrus | 1 – 3 weeks | Rest between heats if not pregnant |
Diestrus | 61 – 72 days | Pregnancy |
Anestrus | Several weeks to months | No heat (non-breeding season for outdoor cats) |
The entire cycle, including all the stages, can range from about one to six weeks. So, a cat that is not bred may go into heat every few weeks during the breeding season.
How Often Do Cats Go Into Heat Per Year?
Cats that have not been spayed will go into heat each year, usually between February and October. They can have many cycles in one season, sometimes going into heat every two to three weeks if they do not get pregnant. This means a cat can go into heat two to four times during each season, but it can feel almost continuous at times. As cats get older, they still have heat cycles, but these may get less frequent.

Cats reach their first heat cycle between four and twelve months of age, with most starting at about six months old. Some breeds, like Siamese, start as early as four months, while bigger breeds might start later. A cat can become pregnant during her very first heat, so early spaying is best to avoid unwanted kittens.
Does Breed or Environment Change the Heat Cycle?
Both breed and environment impact how long and how often cats go into heat. Siamese cats and some other breeds mature earlier and may have their first heat around four months. Larger breeds may not have their first heat until they are about 10 months old.
Environment is also important. Outdoor cats’ breeding seasons are influenced by daylight, usually running from January or February until October. Indoor cats, under artificial light, may come into heat at any time during the year, sometimes without a break. The number of other cats in the area, especially unspayed or unneutered cats, can also influence when and how often your cat goes into heat.

Knowing how a cat’s heat cycle works helps you care for your pet. While some behaviors may be hard to manage, understanding the cycle makes things easier. Spaying your cat is the best way to prevent unwanted litters, reduce stress behaviors, and help keep your cat healthy. Spaying also lowers the chances of certain health problems, like womb infections and breast tumors. Most vets suggest spaying your cat between four and six months old, after her first vaccines, but older cats can be spayed, too. If you have any concerns about your cat’s heat cycle or health, ask your vet-they can give you the right advice for your pet.