Spa Cover Measuring Guide

When measuring your spa for a new spa cover, there is one important thing to remember: IT HAS TO BE LARGE ENOUGH TO FIT! We can make you a cover in one of two styles.

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Spa Cover Measuring Tips & Tricks


When measuring your spa for a new spa cover, there is one important thing to remember: IT HAS TO BE LARGE ENOUGH TO FIT IT! We can make you a cover in one of two styles. The most popular style is to cover only the acrylic shell. (Measurement C in the below diagram).

If you have a spa that resembles the diagram below (right side), with a wood edge on the outside of the acrylic shell, and would like your new lid to cover both the shell and the wood lip, MEASURE FROM THE OUTSIDE OF THE WOOD SKIRT (D “Cabinet Size”).

There is no difference in spa cover performance either way. It is simply your preference.

spa cover measurements
  • C - Outside dimension of the acrylic shell (standard cover size).
  • D - Outside dimension of the wood cabinet.
  • S - This is the height of the acrylic lip, determining the covers skirt length.

S – This is the height of the acrylic lip, determining the covers skirt length (“Cabinet Size” covers may require a longer skirt, to the bottom of the “deck”).

acrylic lip height diagram

Measuring a Round Corner Radius


Round Corner Radius

Some cover have rounded corners. The diagram above shows a rounded corner with imaginary dotted red lines. The length of the red line represents the measurement of the radius corner. The lines start where the cover begins to curve, and end where they cross. Be sure to measure all the corners and that they are ALL the same size! IMPORTANT: If in doubt, a slight smaller radius will slightly over hang the spa while a larger radius will not cover the spa completely.

There are numerous ways one may go about measuring the radius of a rounded corner, but here are the easiest we have found so far.

METHOD #1


If your existing cover fits properly, set it upside-down on top of a piece of newspaper. Line up the edges of the newspaper with the edges of the cover. The distance from the corner of the newspaper, to where the cover completely covers the paper is the radius of the corner.

radius measurement method 1

METHOD #2


You can also use a framing square to measure the radius of your spa corners. Set the square against the edge of the spa as shown. The radius of the rounded corner is the distance from inside corner of the square, to where the cover just touches the square.

radius measurement method 2

This diagram shows the pitfalls with miss-measuring a rounded corner. The green line represents a measurement of the too large a radius, while the red line represents a measurement too small. As you can see with too large a radius the cover wont completely over the spa. Too small a radius and the cover simply overhangs a bit. If in doubt always go with the slightly smaller measurement. The cover may be slightly large and overhang the corner a bit, but it will cover the entire spa and no one but you will ever know.

radius measurement length

Measuring a Cut Corner


cut corner measurement

Some covers have cut-corners. The diagram above shows a cut corner with the length of the redline representing the measurement of the cut-corner. Be sure to measure all corners and that they are ALL the same size (some covers have different cuts)! IMPORTANT: If in doubt, a slightly smaller cut-corner will cause the corner to slightly over hang the spa while a large cut will not cover the spa completely.

One of the more difficult things is trying to measure a diagonally cut-corner when the corner is also rounded. There are numerous ways one may go about figuring this measurement, but this is the easiest we have found so far.

Using masking tape, simply extend the lines of your spa (or existing cover) as shown below. Where the tape crosses is where you want to measure from. In the diagram, “A” is the measurement of the diagonal cut-corner. If you don’t have any tape, a yardstick (or other small piece of wood) will also work.

measurement of cut corner

This diagram shows the pitfalls with miss-measuring a cut-corner. The green lines represents a measurement too large while the red line represents a measurement too small. As you can see, with too large a cut-corner the cover won’t completely cover the spa. Too small a cut-corner and the cover simply overhangs a bit. If in doubt always go with a slightly smaller measurement. The cover may be slightly large and over the corner a bit, but it will cover the entire spa and no one but you will ever know.

cut corner length

When measuring an octagon spa, it is extremely important to get dimensions on all sides of the tub.
This example shows an octagon (eight sides). Its length and width measurements (9 & 10), and the sides measurements (1-8), are ALL EQUAL. If they are not equal, it is not a true octagon, but more than likely a cover with cut corners.

octagon cover

More measuring tips:


  • Measure both your spa and your old cover, if possible.
  • Make sure the measurements are big enough. It is okay for the cover to be big. It still does its job. However, a cover too small will never do the job it is supposed to.
  • Measure all sides of the spa.
  • Measure the overall length and width of the spa.
  • Be careful when representing the dimensions in our order forms.
  • Specify hinge direction.
  • If the online order form is not flexible enough for your needs, give us a call at 1-781-933-2006