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  3. Mattress Firmness Guide
Sleep

Mattress Firmness Guide: How to Choose by Sleep Position

How to choose mattress firmness by sleep position and body weight, the differences between memory foam, hybrid, latex and innerspring, and what to check in trials.

Quick answer

Choose firmness by how you sleep. Side sleepers usually do best on soft to medium mattresses that cushion shoulders and hips; back sleepers on medium to medium-firm; stomach sleepers on firmer mattresses that keep hips from sinking. Heavier people often prefer firmer, more supportive beds. Memory foam hugs, latex is buoyant, and hybrids add springs for bounce and airflow. Use the sleep trial to decide.

The right mattress keeps your spine aligned and relieves pressure points. Sleep position is the best starting point.

Firmness by sleep position

Sleep position Firmness (1 to 10) Why
Side Soft to medium (about 4 to 6) Cushions shoulders and hips
Back Medium to medium-firm (about 5 to 7) Supports the lower back
Stomach Medium-firm to firm (about 6 to 8) Keeps hips from sinking
Combination Medium (about 5 to 6) Balance and easy movement

Firmness labels vary between brands, so compare descriptions, not just numbers.

Body weight

Heavier people sink further into mattresses and often prefer firmer, thicker beds with coils. Lighter people may find firm beds too hard.

Mattress types

Type Feel Good for
Memory foam Slow, contouring hug Pressure relief, motion isolation
Latex Buoyant, responsive Bounce, durability
Hybrid Coils plus foam or latex Support, airflow, edge support
Innerspring Bouncy, firm Budget, traditional feel

Other things to check

  • Cooling: hybrids and latex tend to sleep cooler than all-foam.
  • Motion isolation: foam is best for couples.
  • Edge support: coils help if you sit on the edge.
  • Trial and warranty: length, return fees and conditions.

Timing

Most mattresses last about 7 to 10 years. Replace yours if it sags or you wake up sore.

Common questions

What mattress firmness is best for side sleepers?

Soft to medium (often around 4 to 6 on a 10-point scale), so shoulders and hips sink in enough to keep the spine aligned.

What is a hybrid mattress?

A mattress that combines a coil spring support core with comfort layers of foam or latex, giving bounce, airflow and pressure relief.

How long does it take to get used to a new mattress?

Often two to four weeks. That's why many brands offer sleep trials of 100 nights or more; check return conditions before buying.