A scratching post that is too short is barely used, and the sofa pays the price. Cats scratch to stretch their whole body, and a full stretch needs height. This free scratching post size calculator turns your cat stretched height into a minimum post height and a stable base size, so the post you buy actually gets scratched.
Watch a cat scratch and you will see why height matters. The cat reaches up, hooks its claws in, and pulls down while its back and shoulders stretch out. A short post stops that stretch halfway, so the cat walks away and finds something taller, like the arm of a chair or a door frame. A post that allows a full stretch is a post the cat returns to.
Measuring is easy and takes a minute. Wait until your cat stretches up against a wall or a door, and mark how high the front paws reach. Or gently encourage a stretch with a toy held above the head, then measure from the floor to the paws. Enter that height in centimetres, press Calculate post size, and the tool gives you the numbers.
The rule is simple. The post itself must be at least as tall as the stretched height, and this tool adds a small margin on top so the cat never runs out of post mid-stretch. The base matters just as much: a tall post on a small base wobbles, and a wobbling post frightens cats away. A wide, heavy base keeps the post steady during a hard scratch.
Here is an example. A cat that stretches to 80 centimetres needs a post at least 80 centimetres tall, and this tool recommends 85 centimetres with a 45 by 45 centimetre base. A very tall or large cat stretching past 100 centimetres gets a 50 by 50 centimetre base in the result, because the extra height needs extra stability. Always check the post height itself, not the total height including the base.
Material matters too. Sisal rope is the most popular choice because claws grip it well and it lasts. Carpet-covered posts can confuse cats, since they may then scratch the carpet elsewhere. Place the post near a resting spot or beside the furniture your cat already targets, and reward the first uses with praise or a treat so the habit sticks.
Two mistakes show up again and again. The first is buying a cute, short post that looks good in the room but is useless for stretching. The second is placing a good post in a dark corner where the cat never goes. Put the post where the cat already spends time, keep it stable, and replace the sisal when it frays flat.
This calculator gives minimums based on your own cat, not on an average cat that may not exist. Re-measure kittens as they grow, and re-check if you adopt a larger cat. It is free, it needs no sign-up, and it runs entirely in your browser.
Owners often ask whether a horizontal scratcher can replace a tall post, and the honest answer is that many cats like both, but only a tall vertical post allows the full upward stretch that keeps shoulders and claws healthy. If your cat scratches carpets, a flat sisal board on the floor may work better than any post, so watch which direction your cat naturally scratches before you buy. Rubbing a little dried catnip on a new post helps some cats investigate it, but it is not a substitute for correct height and stability. Never consider declawing as an alternative to a good post, since it is painful surgery that removes part of the toe and causes lasting problems. Two posts in different rooms beat one perfect post in a room the cat rarely visits, because scratching is also a way cats mark territory they actually use.