Mattress Firmness Scale: How to Find Your Ideal Firmness

The mattress firmness scale runs from 1 (extremely soft) to 10 (extremely firm), and most mattresses sold today fall between 5 and 8. Your ideal number depends mainly on two things: your sleep position and your body weight. Side sleepers usually do best around 4-6, back sleepers around 5.5-7 and stomach sleepers around 6.5-8, with lighter people going a step softer and heavier people a step firmer.

Medium-firm, roughly 6 to 7, is the most popular range because it suits the widest group of sleepers. But it isn't right for everyone. Below you'll find what each level feels like, a firmness chart by sleep position and weight, and why brand labels can mislead you.

The mattress firmness scale explained

Here's what each range typically feels like:

• 1-2, extremely soft: you sink deeply. Rare, and unsupportive for most adults.
• 3-4, soft: plush and cradling, with deep contouring at the shoulders and hips. Suits lighter side sleepers.
• 5, medium: a balance of hug and support. Good for side and combination sleepers of average weight.
• 6-7, medium-firm: noticeable support with a cushioned top layer. Fits most back sleepers and many combination sleepers.
• 7.5-8, firm: you rest on top of the mattress with little sink. Suits stomach sleepers, heavier back sleepers and people who simply prefer a firm feel.
• 9-10, extremely firm: very little give. Rarely sold, and uncomfortable for most people.

Firmness vs support: not the same thing

Firmness describes how the surface feels when you lie down: soft and sinking, or firm and flat. Support describes whether the mattress keeps your spine in a neutral line. A soft mattress can be supportive if its core holds your hips up, and a very firm mattress can be unsupportive for a side sleeper if it pushes the shoulder and hip out of line.

That's why "firmer is better for your back" is a myth. The goal is alignment, which depends on how your body shape and weight interact with the mattress.

Mattress firmness chart by sleep position and body weight

Use this chart as a starting point. Weight bands are approximate: lighter sleepers press less into the comfort layers, so a mattress feels firmer to them, and heavier sleepers sink further, so it feels softer.

If two ranges overlap for you, for example you sleep on your side and back, lean toward the position you spend the most time in, or the middle of both ranges.

Side sleepers

Side sleeping concentrates weight on the shoulder and hip, so pressure relief matters most. A mattress that's too firm can leave your shoulder sore and your arm numb. Look for medium or softer, with a thick comfort layer. Our best mattress for side sleepers list focuses on this range.

Back sleepers

Back sleepers need the lower back supported so the hips don't sink below the shoulders. Medium-firm fits most people. Zoned support, which is firmer under the hips, can help. See the best mattress for back sleepers.

Stomach sleepers

Stomach sleeping puts the most strain on the lower back if the hips sag, so stomach sleepers need the firmest, flattest surface. Start with our best mattress for stomach sleepers and best firm mattress picks.

Combination sleepers

If you switch positions, choose a medium to medium-firm mattress with some bounce. Responsive hybrids and latex make it easier to turn over than slow-moving memory foam.

What is a medium-firm mattress, and who should get one?

A medium-firm mattress sits around 6 to 7 on the scale. It has a cushioned top that softens pressure points but enough support underneath to keep your hips from sinking. It's the most common target for brands because it suits back sleepers, combination sleepers and many average-weight side sleepers.

Who should skip medium-firm? Lighter side sleepers, especially those with shoulder or hip pressure, often find it too firm. Stomach sleepers and people over about 230 pounds may find it too soft and do better with a firm mattress.

Examples from the mattresses we track that independent testers rate in the medium-firm range include the Purple Mattress (about 6/10), Saatva Latex Hybrid (about 6/10), Casper The One (about 7/10) and Avocado Green (about 7/10).

Why firmness labels don't always match

There's no industry standard for firmness, so brand labels are marketing, not measurements. A few examples from our data:

• The Siena Memory Foam is sold as medium-firm, but independent testers rate it about 8/10, which is firm.
• Helix rates its Helix Midnight at 6/10, while one independent reviewer puts it at 6.5.
• The Zinus Green Tea is rated 6.5/10 by Zinus and about 5.5 by an independent tester.

Firmness perception is also personal. Weight, body shape and what you're used to all shift how a number feels. Use independent ratings to narrow the field and a sleep trial to make the final call.

Mattresses with more than one firmness

If you're unsure or share a bed with someone who prefers a different feel, some options help:

• Multiple firmness options: models such as the Saatva Classic, Bear Elite Hybrid and WinkBed come in several firmness levels, so you choose before ordering.
• Flippable: the Layla Memory Foam has a softer side and a firmer side.
• Adjustable: the Sleep Number c2 lets each partner set firmness on their own side.

How to fine-tune firmness after you buy

• Too firm: give it a few weeks, since many mattresses soften slightly. A soft mattress topper can add cushioning.
• Too soft: a firm topper can help a little, but it can't fix a mattress that lets your hips sag. Check the base too: a sagging foundation makes any mattress feel softer.
• Still wrong after a month or so: use the sleep trial. Our mattress trial and return policies guide explains what to check.

For the full buying process, read how to choose a mattress, or let the quiz match your position and weight to a firmness target and specific mattresses.