How many hairs on a cat?

The total number of individual hairs on a regular-sized domestic cat is: 68,250,000 (68.25 million). The calculation is 25,000 hair strands per square centimeter multiplied by 2,730 square centimeters total surface area of the cat. But please scroll down to read the note.

I was able to make the calculation with some confidence because of 2 factors (1) there is agreement that the number of hair strands per square centimeter is 25,000 and (2) a veterinary website kindly provides the area of a cat in square meters based on the cat’s weight. See below:

Without the chart I worked out the surface area from scratch which is imprecise and tricky.

Note 2 years later! – I think the number of 25,000 hairs per square centimeter is too high by a factor of 10 (it should be 2,500 at a max.). If that thought is correct the total number of hairs on a cat would be 6.825 million max. instead!!

Both the below attempts (first and second calcs) are probably wrong! That sounds very defeatist but the problem is I am not taking enough time over making this calculation! That doesn’t help anybody reading this but I do not expect anybody to actually read this! That’s enough exclamation marks.

My current thinking is that there are 130,650,000 hairs on a standard domestic cat. I’ve worked this out in a more scientific way assessing the cat’s body as a cylinder and the head as a sphere. To which I added the legs. You can read more about this by clicking on this link which takes you to a new page or tab so that you can remain on this page.

First Calculation

An average domestic cat has 30 million hairs. My calculation is based on very loose measurements of my cat. In fact, I have not measured him. I have simply decided that his body is about 15 inches long and the circumference of his body is also about 15 inches. The average cat has 130,000 strands of hair per square inch.

My cat’s body is 225 square inches (15 x 15). If you multiply that figure by the number of hair strands per square inch you come to the figure of 30 million if you add in 750,000 hair strands for the tail, head, neck and legs.

I have rounded the figure because it will vary obviously between individual cats. The key piece of information is the number of hair strands per square inch. All you have to do is measure your cat in inches. From that you can work out the area of your cat in square inches and this figure is then multiplied by 130,000.

Now the puzzle is: how many hairs on a Sphynx? It is not zero. Sphynx cats have bum fluff over them but it is sparse. I’d expect the number of hair strands to be a fraction of 30m and add in ten whiskers.

Second Calculation

My first calculation below was based on what appears to be an accepted number: the number of hair strands per square inch. The widely published figure is around 130,000 but it might fall to 60,000 depending on the part of the body. I have spent the last 15 minutes looking at my cat’s fur and he became a little irritated 🙂 . I now don’t believe that there are 130,000 hair strands per square inch. It is very hard to estimate the number. My gut feeling is that the number is somewhere nearer 10,000 hairs per square inch or less. That would make the overall figure about one tenth of my first calculation, which is 3 million hair strands. My current thinking is that there are about 3 million hairs on a cat (domestic).

Sadly, this is largely guesswork because there is no available science on this. It is left to the layperson. Me or you.

SOME MORE ON FUR: