When measuring the spa for a new spa cover, there is one important thing to remember


A bit too big is much better than too small

Hot tub covers can fit in one of two ways. The most popular is a cover that fits only over the acrylic shell (in a lot of hot tubs, the acrylic shell comes out further than the wood or plastic skirt) and in this case, you must measure from the outside edge of the shell. However, if your hot tub resembles the diagram below, with a wood or plastic sill on the outside of the acrylic shell, and you would like the new lid to cover both the shell and the sill, then you must measure from the outside of the wood skirt. The cover will perform equally well either way, as long as it is big enough to fit completely over the spa shell.

Side view of hot tub


This is the height of the acrylic lip and will determine the cover´s skirt length if you want your cover to to sit on top of a sill. Otherwise you may choose any skirt length up to 25.5 cm so that it will easily sit over the edges of the spa with a little room to spare.


Outside dimension of the acrylic shell. This is the normal measurement to specify unless you have a sill and prefer your cover to fully enclose it.


Outside dimension of the hot tub cabinet. You should use this measurement if you have a sill and prefer your cover to fully enclose it.

More measuring tips:

  • Make sure the measurements are big enough. It is okay for the cover to be a bit big. It still does it's job. However, a cover that is too small will never insulate properly.
  • Don't forget that, even though your hot tub might look square, it might not actually be square, so always measure both the length and width to confirm that they are either the same or different. Always err on the side of adding surface area to the cover and don't skimp on the measurements.
  • You can specify if the hinge is at the centre of the longest side or the shortest side when you order
  • Round down any dimensions of cut corners or radius corners. If the radius is too big (ie there is too much curvature) it will never fit the corner properly, but if the curvature is a bit too small that is fine.
  • For rounded corners, check out the picture to the right.

measuring hot tub cover radius

Above is an illustration of the best way to measure the radius.

Measure the distance from the imaginary corner, A, to the point at which the curvature stops, B.