How to measure a hot tub cover the right way

If it's time for a new hot tub cover, correct measurements are needed to ensure the perfect fit, even if your hot tub dealer has your model's dimensions on file. In case you've got measuring tape jitters, we'll walk you through the steps so you know how to measure a hot tub cover the right way.

Measure the hot tub

  • 1 Measure lip to lip. Regardless of the shape your spa, you should measure from lip to lip, or the outside dimension of the acrylic which is the same as lip to lip. After you have a lip to lip measurement you may add up to 1" on both length and width. This will give you a 1/2" of play all around your spa cover.
  • 2 Measure the skirt. The skirt is the flap that hangs from the bottom of your cover. The skirt protects the spa surface and aids in heat retention, if not measured correctly can cause some problems because if it is too long it will bunch and push your spa cover up. If you have a wood rail as in the picture above measure from the top of the wood rail to the top of your spa acrylic. If anything you want to be a little short rather than long so the skirt does not bunch. If you do not have a wood rail then you want to measure from the top of the spa to the bottom of the spa lip and add 1/2".
  • 3 Measure the radius. This is how you measure a curved edge on your hot tub, and it's the step that makes everyone worried. As the lower diagram on the left shows, the easiest way to measure a radius, which 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 corners of the hot tub cover. Your hot tub cover radius will always be an even number. To measure radius "C": extend straight lines indicated in red by laying straight edges against the sides of the hot tub. Measure from point "Y" to point "Z".

How to measure different shapes of hot tubs

  • Square cover. The square hot tub cover is the easiest cover to measure. Just measure your hot tub from lip to lip. The only other dimension you will need is the skirt length.
  • Rectangular cover. Measure for a rectangular hot tub cover the same way as for a square cover, but make sure you request the fold direction you require. Most companies will cut the longest of the two sides in half unless you tell them otherwise.
  • Square or rectangular cover with rounded corners. Follow the square and rectangle spa cover procedure and add the radius measurement.
  • Round cover. The round spa cover is easy to measure as well, since you only need the lip-to-lip measurement. If your old cover is measurable, you can also measure across the seam. The only other measurement needed is the skirt length.
  • Octagonal cover (8 equal-length sides). For an octagonal hot tub cover, measure from lip to lip. Also, measure one side of the octagon from point to point. The only other measurement needed is the skirt length.
  • Oval or special shapes. Most oval (ellipse)-shaped and special shaped hot tubs will require a template provided by you to complete your cover properly. Special shaped hot tubs include those with speaker bumps, waterfalls or cutouts for rails or controls.

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