How to measure hot tub cover

Measuring the corner radius seems to be one of the biggest challenges customers face. Let’s try to make it easy for you to understand and get an accurate measure for your own tub.

Print corner measuring template

Measurement guide PDF

Example corner radius

This picture shows a hot tub with a five inch radius corner. Actually, it’s more like a 5.5 inch radius, and in fact it’s wise in this example to round up a half inch. A slightly larger spa cover will ensure some looseness as they do tend to shrink over time. As an added bonus, a slightly larger cover makes it easier to pull the skirt snug around the edges.

Watch this helpful video to learn more about measuring your cover

Measuring skirt length

The part of the cover hanging around the side/bottom is known as the skirt. It’s mostly there for cosmetic reasons, but also helps prevent heat loss when it fits properly. Too long, and it might bunch up and prevent the cover from fitting well. Too short, and it won’t do much good at all. If you have a wood rail, as shown in the diagram above, measure from the top of the wood rail to the top of the spa’s acrylic part. If your spa doesn’t have a wood rail, you can measure from the top of the spa to the bottom of the lip and add a half inch to the total.

Download a complete measuring guide

Printable guide

Use this guide to get a better understanding of the measurements you’ll need, and the various parts of the cover that are important to pay attention to when selecting a new one.

Download the guide (PDF)

Q. Can I supply you with the make/model of my hot tub for a new cover?

A. You can, but we recommend measuring it yourself. We have standard manufacturer measurements for many popular spa brands, but your measurements are actually the most accurate. We have excellent testimonials about our fitment, and are confident we can supply you with a great new hot tub cover.

Q. Do I measure the old hot tub cover, or the hot tub?

A. Of course if you have the old spa cover, and you were happy with its fitment, use that as a guide. If you don’t have an old cover, or your old hot tub cover is too beat up, feel free to use the hot tub itself. It’s common for hot tub covers to shrink over time, so the hot tub enclosure is a good place to get accurate measurements.

Q. Where should I measure?

A. Look for the widest point and measure the length and width. Round up every measurement to the nearest half inch.

BE SURE to note where the measurement lines start and end for the hot tub shape you have.

In general, if the hot tub cover is slightly too big that’s OK. If it is a tiny bit too small, it won’t be a hot tub cover.

Q. What do I do if there are raised areas on my hot tub cover?

A. If you have a special feature in your hot tub cover, such as raised areas, corner pockets, or an odd shape, just contact us. We’ll be happy to take the special options you need and give our manufacturer specific instructions so you get exactly what you need.

Q. What do I do if I have more questions?

A. For additional information please email us at sales (at) hottubcoverdepot.com or use out contact page to send us a note.

When ordering a new hot tub cover, it is important to get a cover that fits well to maximise energy efficiency. This not only ensures that your hot tub stays at the set temperature but will save you lots of money. Below is a guide on how to measure your cover correctly.

Measuring Your Hot Tub's Size

If you are happy with the fit of your existing cover, by all means measure your existing cover but remember this will probably have expanded over time by soaking up water.
When measuring your spa, always remember to measure from one lip to the other. The lip may be the edge of the acrylic or the wooden cabinet depending on your model. It is recommended to add around 0.5’’-1’’ to both the length and width to allow for easy removal, as too tight a fit will make it difficult to remove the cover.

Measuring Skirt Length

The skirt that overhangs your acrylic or cabinet is important to prevent heat loss around the edges. The length of your existing cover skirt is usually recommended or a skirt of around 4’’ is normal. If you have a wooden ledge around the acrylic, too long a skirt could lead to problems with the cover fit, ensure that this is considered when measuring the cover.

Measuring the Radius of Your Hot Tub Cover

The what? The radius! Commonly frustrating for most hot tub owners when they first order a new cover. Getting this right is again vital to prevent heat loss through the corner of the cover.
The easiest way to measure is using a carpenter’s square, however you can easily make of one of these using strong cardboard. The radius length is from the start of the bend to the imaginary point of the corner if the cover was square. The smaller the radius, the more square the corner of the hot tub cover.

The picture below illustrates how to measure your radius and if you need further assistance please view our helpful tutorial video also shown below. Or give us a call on 02380 812769 to talk through. 

How to Measure Certain Shaped Covers

Square - Easy. Measure one length, you won’t have a radius and will only need a skirt length to complete your order. Be careful, most hot tub covers are not totally square and without a radius, double check to prevent errors.

Rectangle - Measure both lengths and specify which length needs to be the folding length. By default, we will assume that the cover folds along the long side.

Square with Radius - Follow the instructions of a square cover and measure the radius.

Rectangle with Radius - Follow the instructions of a square cover and measure the radius.

Round - Measure the diameter of the hot tub cover and this will be sufficient. 

Octagonal - Measure the length and also measure the length of each section on the octagon. 

Happy Tips

• Remember you can make your own carpenters square using a ruler, cardboard and scissors!
• Specify your hot tub model and make when ordering your cover. We have over 1000 models in our file and can compare with previous orders to ensure your measurements are totally accurate.
• Remember that your old and worn cover will not be totally accurate to fit your hot tub. Measure your hot tub and your existing cover and compare the difference, draw conclusions from both.
• Many people send us length and width measurements that are 1 inch out, these hot tubs are most probably square but the cover wear has led to a slight change in size, assume the cover is square if the measurements are this close.
• When measuring a cover size, bigger is generally better because if you are too snug the skirt may fold under the cover or it may struggle to sit around the acrylic on the hot tub. 
• When measuring a corner, smaller is better! Round down if needed.

Once you have measured you can compare your measurements with our selection of Stock Covers ready for Next Day Delivery - CLICK HERE

Or if you have no luck finding a stock cover to fit your hot tub, see our Custom Cover options - CLICK HERE

Guide to Measuring Hot Tub and Spa Covers

This guide will help you measure hot tub and spa covers so that they will fit perfectly. Even if your hot tub manufacturer has your model on file, take the time to measure to be sure. We have seen too many customers be given the wrong hot tub dimensions.

Regardless of the shape of your spa, you should measure from lip to lip, or the outside dimension

This is the one that makes everyone worried. As the diagram shows the easiest way to measure a radius is with a carpenter square. The dimension needed is from the start of the bend to the imaginary point of the square if the tub was actually square. Rule of thumb is smaller is safer than larger. The smaller the radius the more square the corner of the hot tub cover.

Square or Rectangle with a radius on four corners

To measure radius “C”: extend straight lines indicated in red by laying straightedges against the sides of the spa. Measure from point “Y” to point “Z”. 

The square hot tub cover is the easiest cover to measure. Simply measure your outside lip to lip, and add 1/2″ to each dimension. The only other dimension you will need is the skirt length.

This is the same technique as the square spa, but make sure you request the fold direction you require. Most companies will by default cut the longest of the two sides in half.

Follow the square and rectangle spa cover procedure and add the radius measurement.

It is simple to measure a cover for a round hot tub. You only need the lip to lip measurement. If your old cover is measurable just measure across the seam. Remember to add 1/2″ of play. The only other measurement needed is the skirt length.

For the octagon spa cover, measure from lip to lip and add 1/2″ of play. Also, measure one panel of the octagon from point to point. The only other measurement needed is the skirt length.

Most of these hot tub covers will require a template provided by you for the manufacturer to build your cover properly. This includes spas with speaker bumps, waterfalls, or cut outs for rails or controls. Make sure to measure hot tub and spa covers to the very outside of the acrylic.