How to Measure and Replace Your Hot Tub Cover: Expert Guide
Tips Before You Start Measuring
Before grabbing your tape measure, these quick tips can save you time—and prevent costly mistakes or back-and-forth:
1.Don't measure the wood frame or deck. Measure the actual acrylic shell, not the width of the outer frame or decorative edge.
2.Use inches only. Stick to one unit to avoid conversion errors.
3.We recommend adding an extra inch to the exact dimensions. This will make the lid fit more securely without being too tight.
4.Check for extras. If your spa has waterfalls, handles, speakers, or pillows that stick up, account for their space.
5.Acrylic hot tubs usually need a skirt. This skirt covers the shell, and typically requires adding about 1/2 inch to the overall size.
6.Measure twice (or three times). Double-check all dimensions to ensure accuracy from different angles.
7.Confirm everything with us. Your final custom size will be based on what we confirm together—so be sure to review all details before placing the order.
Common Hot Tub Shapes & How to Measure
Here are the most common spa cover shapes, and how to measure each one:
Square or Rectangular Hot Tub Cover
This is the most common and easiest shape to measure.
Measurements needed:
Length (L)
Width (W)
Skirt length
Tip:
Be sure to confirm the hinge direction (i.e., how the cover opens). Hinges usually run along the longer side, but some covers fold along the width. The hinge direction determines the center fold and how the cover fits and works with your lifter.
Round Hot Tub Cover
Popular in Europe, especially for small outdoor spas.
Measurements needed:
Diameter (D)
Skirt length
Tip:
If the tub looks round but is slightly oval, measure both vertical and horizontal diameters and take the average. Add a note that it's 'slightly irregular,' and we'll adjust the cover for a better fit.
Rounded Corner Square or Rounded Rectangle Spa Cover
One of the most common shapes today, and also the easiest to measure incorrectly because of the corner radius.
Measurements needed:
Length (L)
Width (W)
Corner radius (R)
Skirt length
Tip:
The corner radius is crucial for a proper fit but often overlooked. Luckily, it's easy to measure with two right-angle rulers:
1.Place one ruler horizontally along the edge of the cover.
2.Place the other ruler vertically, forming a right angle.
3.You'll see a gap between the curved corner and the rulers.
4.Measure the distance from the curve to each ruler—the horizontal and vertical gaps should be the same.
5.That number (typically between 2" and 10") is your corner radius.
Refer to the diagram below for a visual guide. If you're unsure of your measurement, feel free to send us a photo, we're happy to help confirm.
Special-Shaped Spa Covers
In addition to standard shapes, some spa covers have unique forms that require extra-precise measurements:
Octagon Spa Cover
Common for high-end outdoor hot tubs or massage spas.
Measurements needed:
Length of each side
Total diagonal (corner to corner)
Skirt length
Tip:
Check if all eight sides are equal. If they vary, list each side's measurement separately.
Oval Spa Cover
Measurements needed:
Long axis (L)
Short axis (W)
Skirt length
Tip:
Measure from the center lines of the tub to ensure symmetry. This helps with both manufacturing accuracy and use.
Irregular Spa Covers
Examples include U-shapes, dual-fold covers, or unique designs like swim spa covers.
Measurement suggestions:
Provide a hand-drawn sketch with all side lengths, curves, and angles clearly marked
Snap a few photos of the spa in place.
Or tell us measurements of the old cover
Tip:
For these custom shapes, we recommend confirming a 3D sketch with our team before prototyping. We have extensive experience delivering high-precision, low-tolerance covers for irregular designs.
Additional Hot Tub Custom Options
At Hydrorelax, we support a wide range of customization details:
Cover thickness
Hinge thickness
Skirt length
Adding a heat seal
Strap quantity & length (Available in any position and size)
Logo area & color options :personalize your cover with a branded logo to boost recognition and marketing impact.
How to Share Your Hot Tub Cover Requirements with Hydrorelax
Here's how to get started:
Sketch the shape :
Hand-draw the outline of the hot tub lid and label all key dimensions (length, width, height, corner radius, diagonal, etc.).
Mark hinge direction:
Indicate how the cover opens (hinge side) to ensure correct folding design.
Add special notes :
Mention if the cover needs a skirt, specific thickness, buckles, handles, or logo printing.
Send photos (optional):
If you have photos of the old cover or the actual spa, they're very helpful for spotting potential issues.
Confirm sample & lead time:
We offer sample production before mass orders to ensure consistency and accuracy.
Ask for expert help :
Not sure about something? Just reach out! We'll provide diagrams, measurement templates, and technical guidance.
Custom Hot Tub Cover FAQ
I only have the old cover—can I measure from that?
Yes, but please note that older covers may have warped over time. We recommend measuring both the cover and the actual spa shell to ensure accuracy.
Can I order the cover in different colors or materials?
Absolutely. We offer a variety of colors (gray, brown, black, etc.) and materials (PVC, UV-resistant vinyl, etc.), as well as custom logo .
What kind of packaging is suitable for export?
We offer PE bags, cardboard boxes, or PE bags + cardboard packaging, suitable for export.
Hydrorelax Custom Case Study
Octagon Custom Spa Cover
Unique octagonal shape with tapered design—tailored market solution On-trend style, built for superior waterproof and drainage performance
Triangular Curved Spa Cover
Unique triangular-arc structure with fully sealed design Smooth, wrinkle-free surface—100% meets customer requirements
Fully Irregular Spa Cover
Precisely crafted with multiple custom curves to fit unique tub structures Irregular shape combined with taper—maximum customization
Custom-Shaped Spa Cover with Reinforced Hinges
Unique shape paired with heavy-duty hinge design for enhanced durability and load capacity
About Hydrorelax
Hydrorelax has specialized in hot tub cover manufacturing for over 20 years. We understand your demand for precision before a project goes to market. When you work with us, you're not just getting a spa cover—you're getting a reliable, highly customized solution that fits perfectly.
If you're planning to customize covers for your spa brand or looking to evaluate new suppliers, feel free to contact us for measurement support and a quote. We also welcome long-term ODM/OEM partnerships.