A made-to-measure cover is only as good as the measurements it's made to. Five measurements, ten minutes, and the diagrams below make each one foolproof. When you're done, put them straight into the cover builder for an instant price.
Measure the hot tub itself, never your old cover. Covers waterlog, warp and compress over the years — an old cover that "looks about right" can be an inch or more out. You'll need a tape measure, a piece of cardboard, a pen, and ideally a second pair of hands. Write everything down in both centimetres and inches.
Measure straight across the top of the acrylic shell, lip edge to lip edge, at the widest points — a straight line through the air, not following any curve. Take the longest side first (A), then the shorter side (B). If your tub looks square, measure both anyway — plenty of "square" tubs are a couple of centimetres out, and the cover should match reality.
The corner radius (R) is how rounded your tub's corners are, and it's the measurement that makes a cover fit like it was born there. The easy way: hold a piece of cardboard tucked square into the corner, trace the curve of the shell onto it, then measure from the cardboard's corner to where your traced curve begins — along either edge. Both distances should match; that's your radius. If you'd rather not trace, lay two straight edges along the two sides so they cross past the corner, and measure from their crossing point back to where the shell starts to curve.
The skirt is the flap that hangs down around the sides. Measure from the underside of the shell lip down to where you want the skirt to finish — long enough to cover the shell edge and any fixing points, without fouling your cabinet panels or a cover lifter. If your current skirt length works well, that one measurement you can take from the old cover.
Every cover folds in half along a hinge. Decide which way you want yours to fold based on where you stand to open it and where a cover lifter would sit — the hinge normally runs across the middle of the longer measurement (A), so the two halves are manageable. Stand at your tub and mime opening it; whichever way feels natural, note it as "fold across A" or "fold across B".
Walk around the tub and note anything that sits above the level of the shell lip or interrupts the sides: raised speakers, drinks coolers, tall headrests, waterfall features, a cover lifter's brackets, steps that tuck under the skirt. None of these are a problem — but the maker needs to know about every one of them before cutting foam. A quick note like "speaker pod raised 3cm, back-left corner" is perfect.
Round or unusual shape? Measure the diameter twice at right angles to each other, and photograph the tub from above if you can.
Not 100% sure about a measurement? Send us photos of your tub with the tape measure in shot and we'll sanity-check everything before anything gets made. It costs nothing and it's saved plenty of covers.