Whether making a new post or re-wrapping an old one, you may wonder how much sisal rope to make a scratching post.

Assuming your scratching post has a standard square or round shape, the formula is rather basic.

The key to accurate results is making precise measurements. Unfortunately, not every scratching post has a standard shape, so some cat owners may need to revive their geometry knowledge.

Note that sisal rope is often sold in large rolls, so you might have some rope left after wrapping the post, but there are ways to avoid material waste.

If the calculations are too time-consuming, consider alternatives to sisal rope, such as sisal fabric. Most importantly, take into account your cat’s preferences.

## Measure the Post Height

The first factor affecting how much sisal rope you need for a cat scratching post is the post’s height. Simply measure the post’s size from the base to the top.

If you want to change the sisal rope on a cat tree, measure the height of every post. A standard scratching post for an adult cat is about 30-35 inches tall, but kitten scratching posts can be shorter, not exceeding 25 inches.

Scratching posts for large-breed or active cats that like to jump and climb on the post may exceed 40 inches in height.

The average scratching post height can help you estimate the costs, but when purchasing, use your actual measurements. It’s best to take slightly more rope than you need if your DIY project goes wrong.

## Measure the Post Circumference

The second measurement you need to make to determine the necessary sisal rope length for a scratching post is the post’s circumference. Use a soft measuring tape or a thick, non-elastic thread to wrap the post.

The measuring tape or thread should be non-elastic because so is sisal rope. If you use an elastic measuring tape or thread, your measurements will be incorrect, and you may buy more rope than needed, which means extra money spent.

With measuring tape, the process is slightly easier. However, if you don’t have one, wrap a thread around the post, then pinch and hold the point where the end meets the rest of the thread.

Keeping the point with your fingers, straighten the thread and align it across a long ruler to find its length.

If your post is oddly shaped, for example, is conical, find a point that seems like an average circumference (usually in the middle).

## What Thickness of Sisal Rope to Use

The type of rope you want to use is the last factor affecting how much sisal rope to buy for a scratching post. Specifically, the sisal rope’s thickness.

Which sisal rope thickness to use for a scratching post is entirely up to you and your cat. The most common sisal rope size for a scratching post is 1/4-inch or 3/8-inch.

As a rule of thumb, thicker sisal ropes are better for cats because they don’t interrupt scratches as quickly as thin ropes (the cat’s claws will constantly fall into the dips). Furthermore, they are more durable and don’t fray as easily.

Choose a thicker sisal rope if your cat likes to scratch long. Some cats have a shorter reach and make short scratches.

Working with a thin sisal rope is easier because it bends better and fastens to the post without any hassle. However, you don’t need as much thick sisal rope as thin sisal rope to wrap a scratching post, so it may be more cost-effective.

If you’re re-wrapping an old scratching post, the best thing to do would be to measure the thickness and length of the original sisal rope.

If you’re making a DIY cat scratching post, choose between the ease of use (1/4-inch) vs. durability (3/8-inch).

Note that you may find sisal ropes of any other thickness you prefer if you don’t like the standard sizes.

## How to Calculate the Necessary Sisal Rope Length

Now that you have all the necessary measurements, you can finally calculate the sisal rope length for a cat scratching post. Here, you’ll need a calculator and basic math knowledge.

First, determine how many times you must warp the rope around the scratching post. To find the number, divide the post’s height by the thickness of the rope.

For example, if you have a 36-inch-tall scratching post and a 1/4-inch-thick sisal rope, divide 36 by 1/4, and you’ll get 144 times.

Or, if you choose a thicker rope, divide 36 by 3/8, and you’ll need to wrap the post 96 times. Now, multiply the post’s circumference by the number of times you will need to warp the post.

Let’s assume that your scratching post’s circumference is 10 inches. If the sisal rope is 1/4-inch-thick and you need to wrap the post 144 times, you will need a 1440-inch-long sisal rope.

Given the same circumference and post height but a 3/8-inch sisal rope, you would have to buy a 960-inch-long sisal rope. Note that sisal rope usually comes in 100-foot rolls, although you may be able to find a 50-foot roll.

To find out how many sisal rope rolls to wrap a cat scratching post, convert inches into feet (divide the value by 12 or use an online calculator), then divide the number by 100.

So, 1440 inches of 1/4-inch thick sisal rope equals 120 feet. If we divide 120 feet by 100, we’ll get 1.2 rolls.

Since you cannot buy rolls in parts, you would have to purchase two rolls and have some extra for the next time or another DIY project.

If the necessary sisal rope length is 960 inches, which equals 80 feet, you would only need to buy one sisal rope roll.

That’s why purchasing a thicker rope is sometimes cheaper. You can calculate both options to pick the most cost-effective one.

However, there’s a way to avoid purchasing an entire extra sisal rope roll for some extra 20 feet. You can wrap part of the scratching post with fabric – for example, carpet.

This way, your cat gets double the enrichment because it can scratch different surfaces, and you save money. Alternatively, search for a place selling sisal rope by the foot – it can be tricky but not impossible.

Consider using a sisal rope length calculator if you aren’t great at math. Such tools give the most accurate results and eliminate the need to wreck your brain.

## What About Non-Standard Scratching Posts?

Some scratching posts have non-standard shapes, such as conical, hourglass, or spherical. Using a sisal rope length calculator won’t help because they only calculate the rope length for square or round posts.

In that case, you will need to use mathematical formulas to calculate the surface area of the necessary shape. However, it’s rarely straightforward for people who aren’t fond of math.

For example, the sphere surface area formula requires you to know the radius of the sphere. And to find out the radius, you need to break the scratcher in halves or calculate it using the formula for finding the sphere radius from the circumference.

For example, a spherical scratching post has a circumference of 20 inches in the thickest place. The formula is C/2π, so the scratcher’s radius is 20/2 π = 3.183 inches.

Now, we can find the sphere’s surface area using the formula 4*Pi*R2. After multiplying four by 3.14 and 3.183*2, we get 79.95 inches.

But that’s not all – now, you need to take into account the rope’s thickness to find out how many wraps to make.

The same problem is relevant for all non-standard scratching posts. Sometimes, buying a new one is a better idea if you have skipped geometry in high school. The good news is that you don’t need to know the exact rope length.

## Consider Sisal Fabric

Whether you’re planning on re-wrapping an old scratching post or making a DIY scratching post, consider using sisal fabric instead of rope. Firstly, calculating the necessary amount of sisal fabric is significantly more straightforward.

There’s no need to calculate the number of wraps or take into account the rope’s thickness. All you need to find out how much sisal fabric to use for a scratching post is the post’s circumference and height.

For example, for a 10-inch-thick, 36-inch-tall scratching post, you would need to buy a 10×36-inch sisal fabric piece. Furthermore, many cats prefer sisal fabric to sisal rope because it allows them to make longer claw streaks.

With sisal rope, cats are constantly interrupted by dents. Some cats don’t mind it because they prefer to make shorter streaks or get used to sisal rope. However, many prefer to make longer streaks.

Sisal fabric is softer than rope, doing less damage to the gentle claws of kittens. Sisal fabric is also cheaper and is not sold in such huge rolls as rope. You can find a piece of the exact size you need.

The disadvantage of sisal fabric is that it isn’t as durable as sisal rope, though still more durable than carpet or corrugated cardboard. Sisal fabric also isn’t suitable for non-standard shape scratchers.