Hot Tub Cover Measuring Guide: How to Measure Your Spa Cover the Right Way - Explained 2026

Ordering a replacement hot tub cover should be simple—but only if your measurements are accurate. A perfectly measured cover ensures proper insulation, protection, and longevity for your spa. On the other hand, a poorly sized cover can cause heat loss, waterlogging, and unnecessary wear and tear.

This hot tub cover measuring guide walks you through everything you need to know—from deciding whether to measure the tub or the cover, to choosing folds, radius, straps, and skirts. Follow these steps carefully to guarantee a perfect fit. And if you ever feel unsure, our team is always happy to assist you.

Why Proper Measurement Matters

When purchasing a replacement hot tub cover, accuracy is key. A cover that’s even slightly too small reduces insulation and wastes energy. A cover that’s a bit larger (1–2 inches) generally fits fine, but precise measurements ensure the best protection and performance.

Whether you’re replacing an old cover or buying one for a new tub, measuring correctly saves money and extends the life of your spa.

Deciding What to Measure: Cover or Hot Tub?

Before you begin, you must determine whether you should measure the existing cover or the hot tub itself.

Measure the Existing Cover If:

• The cover is still in decent condition (normal wear and tear is okay).

• It has NOT warped, become waterlogged, or changed shape.

• You are satisfied with how your current cover fits.

Using an existing cover can be the easiest and most reliable method—as long as the shape has not changed over time.

Measure the Hot Tub If:

• You do not have an existing cover.

• Your current cover is warped, waterlogged, or misshapen.

• You are unhappy with the way it fits your spa.

If there’s any doubt about the existing cover’s accuracy, always measure the hot tub instead.

How to Measure Your Hot Tub or Cover

General Measuring Rule

Round up to the nearest ½ inch or full inch.
A slightly larger cover fits fine.
A too-small cover reduces insulation and is not recommended.

If your dimensions are close (e.g., 78.5” x 78”), you likely have a perfect square.

Where to Measure: Identify Your Hot Tub Style

Your hot tub’s installation style determines how you measure it. Choose the setup that looks like yours:

1. Classic Spa Cabinets

Measure the widest points on the acrylic lip, as shown by the arrows.

2. Spa Cabinets With Top Rail

Measure the widest points on the top rail.

3. In-Ground Spas

Measure the widest above-ground points (where the cover will rest).

Choosing the correct measurement points ensures the cover fits securely and seals properly.

Choose Your Hot Tub Shape

Hot tubs come in many shapes—square, rectangular, round, octagonal, and more.
Match your spa shape to a shape on the supplier’s chart and record your dimensions accordingly.

Correct shape selection is essential for determining fold direction, radius, and hinge placement later.

Choosing a Fold or Hinge

Understanding hinge direction is crucial for safe and comfortable cover use.

Fold Types:

• A Fold – Splits the A dimension in half

• B Fold – Splits the B dimension in half

• No Fold – Used only for perfectly square, one-piece covers

What to Consider When Choosing a Fold:

• Where the control panel is located
  (Covers typically fold away from the controls.)

• Which direction provides the most convenient opening

• Any obstructions like walls, steps, or fences

Most covers fold along the longer side—but there are exceptions, depending on spa design.

Measuring the Corner Radius

Your corner radius determines how rounded the corners of your hot tub cover will be.

Using a Carpenter’s Square:

Place the square at the corner to see where the curve begins and ends. Measure the distance to determine radius size.

If You Don’t Have a Square:

Use household items like a ruler, cardboard, or a letter-sized paper to recreate a right angle.
Then measure where the curve starts.

The more accurate your radius, the better your cover will fit and seal.

Measuring the Skirt and Straps

Skirt Measurement

• Standard skirt length: 4 inches

• Minimum skirt length: 1.5 inches

• A skirt is the fabric flap that hangs below the cover.

Measure from the bottom of the cover downward to determine your desired skirt length.
If you want no skirt, enter 0 inches.

Strap Measurement

• Standard strap length: 9 inches

• Straps must hang at least 1.5 inches below the skirt, excluding the clip.

Measure the strap from the bottom of the cover down, including the skirt length, but not the clip.

Note: Due to production variations, exact strap placement cannot be guaranteed, but straps are required for safety.

Final Thoughts

Measuring your hot tub cover correctly ensures a long-lasting fit, proper insulation, and protection for your spa investment. Whether you’re replacing an old cover or buying a new one, following this guide will help you order with confidence.

If you ever feel unsure or simply want help double-checking your measurements, our support team is always available. We’re here to ensure your new cover fits perfectly—every time.