Deep Fitted vs Standard Mattress Protectors: UK Sizing Guide 2026

MP UK
2026-01-01T18:05:05+00:00

Understanding Mattress Depth and Protector Fit

One of the most common mistakes when buying a mattress protector is choosing the wrong depth. A protector that's too shallow won't fit properly and will constantly slip off, while understanding the difference between deep fitted and standard fitted protectors ensures you get the perfect fit for your mattress. This comprehensive guide explains everything UK shoppers need to know about mattress protector depths and sizing.

What Is Mattress Depth?

Mattress depth (also called height or thickness) is measured from the bottom of the mattress to the top surface. UK mattresses typically range from 18cm to 40cm deep, depending on the type and construction. Traditional spring mattresses tend to be thinner (18-25cm), while modern memory foam, pocket sprung, and pillow-top mattresses are often much deeper (25-40cm).

Standard Fitted Mattress Protectors Explained

Standard fitted mattress protectors are designed to fit mattresses up to 30cm (12 inches) deep. They feature elasticated corners or a full elastic skirt that stretches over the mattress corners and sides. Standard protectors work perfectly for traditional mattresses, basic memory foam mattresses, and most mattresses without pillow tops or thick comfort layers.

When to Choose Standard Fitted Protectors

Choose a standard fitted protector if your mattress measures 30cm or less in depth, you have a traditional spring or basic foam mattress, your mattress doesn't have a pillow top or thick comfort layer, or you've measured and confirmed your mattress depth. Standard protectors are often more affordable and widely available than deep fitted options.

Deep Fitted Mattress Protectors Explained

Deep fitted mattress protectors accommodate mattresses from 30cm up to 40cm (16 inches) deep. They feature extra-deep pockets and longer elastic skirts to ensure a secure fit on thicker mattresses. Deep fitted protectors are essential for pillow-top mattresses, thick memory foam mattresses, hybrid mattresses with multiple layers, and mattresses with additional toppers.

When to Choose Deep Fitted Protectors

Choose a deep fitted protector if your mattress measures more than 30cm in depth, you have a pillow-top or euro-top mattress, you use a mattress topper in addition to your mattress, or your standard protectors keep slipping off. The extra depth ensures the protector stays securely in place throughout the night.

How to Measure Your Mattress Depth

Measuring your mattress depth is simple but essential. Remove all bedding and toppers from your mattress. Using a tape measure or ruler, measure from the bottom of the mattress straight up to the highest point on top. Measure at the thickest part if your mattress has varying depths. Add 5cm if you use a mattress topper. Round up to the nearest size if you're between measurements.

Common UK Mattress Depths by Type

Traditional Spring Mattresses

Traditional open coil and continuous spring mattresses typically measure 18-23cm deep. These mattresses work perfectly with standard fitted protectors and rarely require deep fitted options.

Pocket Sprung Mattresses

Pocket sprung mattresses usually measure 23-28cm deep, though luxury models can be deeper. Most work with standard fitted protectors, but measure to be certain, especially with premium models.

Memory Foam Mattresses

Memory foam mattresses range widely from 20cm for basic models to 35cm for luxury options. Budget memory foam typically uses standard protectors, while premium thick memory foam requires deep fitted protectors.

Pillow-Top and Euro-Top Mattresses

Pillow-top and euro-top mattresses are among the deepest, typically measuring 30-40cm. These almost always require deep fitted protectors due to their extra comfort layers on top.

Hybrid Mattresses

Hybrid mattresses combining springs and foam layers usually measure 25-35cm deep. Most require deep fitted protectors, though some thinner hybrids may work with standard options.

The Consequences of Wrong Sizing

Using the wrong depth protector creates several problems. A too-shallow protector won't pull down fully, leaving corners exposed and vulnerable. It will constantly slip off during sleep, bunching up uncomfortably. The elastic becomes overstretched and wears out quickly. You won't get full protection coverage. Conversely, a too-deep protector may bunch up underneath, creating an uncomfortable sleeping surface.

Extra Deep and Extra Shallow Options

Some manufacturers offer extra deep protectors for mattresses over 40cm (often called super deep or extra deep), and shallow protectors for thin mattresses under 20cm (common for children's mattresses or caravan mattresses). If you have an unusually sized mattress, look for these specialty options.

Mattress Toppers and Depth Considerations

If you use a mattress topper, add its depth to your mattress depth when choosing a protector. For example, a 25cm mattress with a 5cm topper needs a protector that fits 30cm depth. Some people prefer to put the protector over both the mattress and topper for complete protection, while others place it under the topper. Over both provides better protection but requires a deeper protector.

Quality Elastic Makes the Difference

Regardless of whether you choose standard or deep fitted, quality elastic is crucial. Look for protectors with strong elastic around the entire perimeter, not just at the corners. The elastic should be durable and maintain its stretch after repeated washing. Double-stitched elastic attachment points prevent tearing and ensure longevity.

Making the Right Choice for Your Bed

Choosing between deep fitted and standard mattress protectors comes down to one simple measurement: your mattress depth. Take two minutes to measure your mattress accurately, and you'll ensure a perfect fit that provides complete protection, stays securely in place, and lasts for years. When in doubt, size up rather than down for the best fit and protection.