Hot tub cover sizes: how to measure for a new cover

What you need

• A long tape measure, ideally 3 m or more.
• A notepad or phone to record figures.
• A helper to hold the tape straight across.
• Your tub's model number, from the liner label or manual.

Measuring an inflatable tub

Measure when the tub is inflated and filled, as the wall bows out slightly under load.

1. 1

   For round tubs, measure the outer diameter across the widest part of the top wall, from outside edge to outside edge.

2. 2

   For square tubs, measure the outer length and width across the top.

3. 3

   Measure the wall height from the ground to the top of the wall.

4. 4

   Note where the pump unit connects, in case the cover needs a gap there.

5. 5

   Compare with the tub's listed size, such as 196 x 71 cm.

Common inflatable sizes

Many round inflatable tubs fall around 180 cm or 196 cm outer diameter with walls of about 66 to 71 cm. Square models are often around 180 cm a side. Larger tubs run beyond 200 cm. Thermal covers are usually listed by these outer sizes or by model, for example a Lay-Z-Spa X Large square thermal cover listed at 230 x 71 cm.

Measuring a hard shell tub

For acrylic tubs, measure the outer length and width of the cabinet top, the corner radius (or the cut if the corners are angled), and the skirt drop: how far the cover's edge hangs down the side. Note the fold direction and where the hinge should run. Cover makers often supply their own measuring guide, so follow it closely.

Foam thickness and taper matter too. A cover thicker at the centre sheds rain better.

Thermal covers and lids

A thermal cover for an inflatable tub goes over the whole tub, so it must fit the outer size and wall height. A replacement lid must match the tub's top and its clips. Check the listing states your tub's size or model, and look at how it fastens. See thermal cover vs inflatable lid.

Keep the pump unit's vents clear. Some covers include a cut out or flap for the connections.

Avoiding common mistakes

If you are buying a whole tub, the box will include a cover that fits. Our best inflatable hot tubs guide lists sizes.

• Do not buy by seat count; sizes vary between brands.
• Do not measure the inside of the tub; covers fit the outside.
• Do not forget the wall height for wrap over thermal covers.
• Check the shape: round and square covers are not interchangeable.
• Read the returns policy in case the fit is wrong.

See tubs with their sizes →

Recording your sizes for later

Once you have measured, write the figures down with the tub's model number and keep them with the manual. Replacement lids, thermal covers, ground mats and gazebos are all chosen by size, and you will need the same numbers again. A photo of the tape across the tub is a handy reminder.

If you move the tub or buy a new one, measure again rather than relying on old notes. Newer versions of a model can change slightly in size, and a cover that fitted the old tub may not fit the new one. For help choosing a tub by size, see inflatable hot tub sizes and round vs square tubs.

Frequently asked questions

What size hot tub cover do I need? Match your tub's outer diameter or length and width, and its wall height. Use the model number if the cover maker lists it.

Are hot tub covers a standard size? No. Sizes vary by brand and model, so always measure.

Will a 6 person cover fit my 6 person tub? Not necessarily. Check the outer size, not the seat count.

Should I measure the inside or outside? The outside, across the top of the wall or cabinet.