Measuring your hot tub for a new cover is not too difficult though it will be a lot easier with a second person to help you. It can be done with only a measuring tape and a ruler (or a carpenter’s square if you have one). To be sure your cover dimensions are accurate, it is a good idea to measure even if the cover manufacturer has your hot tub on file. Start by identifying the shape of your hot tub and then follow the corresponding directions below.
Tip: do not measure your old cover -- it can shrink and warp and the top dimensions may not accurately reflect the actual size of the cover. A 1/2" too small and you will need to reorder a second brand new cover. Don't take the chance--measure the hot tub.
A square or rectangular hot tub: measure the length and width across the widest parts of the hot tub. Add 1″ to each measurement. Measure the skirt and the radius of the corners (do not measure the radius of the corner on the cover — this must be done on the hot tub itself).
A circular hot tub: measure the width across the centre of the hot tub and add 1″. To ensure you have accurately measured the diameter of the hot tub place one end of the tape measure in a single location. Then extend the other end across the middle of your hot tub. Move it from side to side 6" and take the largest measurement. Measure the skirt.
An octagonal hot tub: measure the width across the centre and add 1″—measure one side of the hot tub. Measure the skirt.
Measuring the length and width
Measure from the widest points of the hot tub. Measure from the outside “lip” where the acrylic body of the tub ends meets the wood. You should add 1″ to these measurements to ensure the cover closes easily.
Measuring the skirt
The skirt is the material that hangs along the edge of the cover. The skirt protects your hot tub finish and prevents the wind from moving or opening the cover. The skirt should come down 1/2″ below the acrylic edge of the hot tub. If you have a “ledge” around your hot tub, measure from the tub of the hot tub to this edge and subtract 1/2″. If the skirt is too long, it will cause bunching and keep the cover from laying flat on the hot tub. It is better to err on the side of a little too short than a little too long.
Measuring the corner
Measuring the corner can be intimidating but is not difficult. First, imagine that your hot tub had square corners. You are trying to measure the distance (C) from where the curve on your hot tub begins (Z) to where the imaginary square corner would meet (Y). You can easily measure this with a carpenter’s square or two rulers.