Choosing a new mattress can be a daunting task. With terms like "plush," "luxury firm," and "ultra firm," it's easy to get lost in a sea of marketing jargon. However, understanding mattress firmness is the most critical step in finding a bed that provides both comfort and support for a restorative night's sleep.
This guide will demystify the mattress firmness scale (typically rated 1-10) and help you determine the right level for your unique needs, based on the two most important factors: your primary sleep position and your body weight.
The Mattress Firmness Scale (1-10)
Most companies use a 1-10 scale, where 1 is the softest and 10 is the firmest.
- 1-2 (Extra Soft): Extremely plush, you'll sink deeply into it. Rare to find.
- 3-4 (Soft): Offers significant sinkage and body contouring. Best for lightweight side sleepers.
- 5-6 (Medium to Medium-Firm): The "Goldilocks" zone for most people. Offers a balance of support and pressure relief. Ideal for back sleepers and average-weight side sleepers.
- 7-8 (Firm): Offers less sinkage and a "sleep on top" feeling. Best for stomach sleepers and heavier individuals.
- 9-10 (Extra Firm): Very rigid with minimal give. Generally recommended only for specific medical reasons.
The goal is not softness or hardness; the goal is spinal alignment.
Choosing by Sleep Position
As we covered in our general mattress guide, your sleep position is the number one factor.
- Side Sleepers: Need a softer mattress (3-6 rating) that allows their shoulders and hips to sink in, keeping the spine straight. A mattress that's too firm will cause pressure points.
- Back Sleepers: Need a medium-firm mattress (5-7 rating) to support the lower back while still contouring to the body's natural curves.
- Stomach Sleepers: Need a firm mattress (7-8 rating) to prevent their hips from sinking too low, which would put a severe arch in their spine.
- Combination Sleepers: A medium-firm mattress (around a 6) is often the most versatile, providing a good balance for multiple positions.
Factoring in Your Body Weight
Your weight determines how much you sink into a mattress, so you need to adjust firmness accordingly.
- Lighter Sleepers (Under 130 lbs / 59 kg): Often need a softer mattress than recommended for their sleep position. A lighter body doesn't sink as much, so a softer surface is needed to get adequate pressure relief. A medium-firm mattress may feel "firm" to them.
- Average Sleepers (130-230 lbs / 59-104 kg): The standard recommendations for sleep positions usually work well for this group.
- Heavier Sleepers (Over 230 lbs / 104 kg): Typically need a firmer mattress than recommended for their sleep position to get the necessary support and prevent excessive sagging. A medium-soft mattress may feel "extra soft" to them.
By considering both your sleep position and your body weight, you can move beyond the marketing and make an informed choice. Remember to take advantage of sleep trials to ensure you've found the perfect fit, giving your body the foundational support it needs for truly restorative sleep.