Mattress Firmness Guide: Soft vs Medium vs Firm

Find Your Ideal Feel

In this guide from The Sleep Shop, we keep it simple and practical so you can shop with confidence. In this guide:

What firmness means

Firmness is about initial surface feel—support comes from the core. Different brands label firmness differently, so always check detailed specs.

Best for side sleepers under ~70 kg who want extra pressure relief. Soft mattresses allow more sink at the shoulder and hip.

The most popular comfort level. Works for most side and back sleepers and couples with mixed preferences.

Suited to stomach sleepers and back sleepers over ~85 kg who need extra lift and reduced hip sink.

Foam density, coil gauge, zoning, and top-layer quilting all change how a mattress feels. Always consider these—not just the labelled firmness.

Will a firm mattress fix back pain?
Not always—medium-firm is optimal for most people.

Do mattresses soften over time?
Yes. Expect slight settling within the first 30–90 nights.