Mattress Firmness Guide

What is Mattress Firmness?

Firmness is how hard or stiff a mattress feels when you lay down on it. Finding the right level of firmness for your mattress is important to your comfort, as a mattress that doesn’t have the right firmness can cause joint discomfort, pain in the shoulder or back, or even cause heat retention. The firmness, support, and conforming ability of a mattress is subjective, and these qualities can vary depending on components and where the mattress is made for any brand or model.

  • Firmness: How hard a mattress feels when you lay down on it.
  • Support: How well a mattress relieves pressure and keeps your spine in alignment.
  • Conformability: How well a mattress conforms to the curves of your body and your sleep position.

You should consider firmness, support, and conformability when choosing the most comfortable mattress for your needs.

What is the Mattress Firmness Scale? uses a firmness scale ranging from 1 to 10, with 1 being the softest and 10 the firmest. However, it’s important to keep in mind that most mattresses will fall between 3 and 8 on our scale.

1-3 (very soft to soft): Very soft and soft rated mattresses are highly conformable. With softer materials, the mattress is better able to conform to the curves of your body. They can offer good support for some sleepers, typically those who are light to average in weight (from less than 130 pounds to 230 pounds). But those who need more support will do better with a more firm mattress.

4-6 (medium-firm): The middle ground of firmness, medium-firm mattresses are a good choice for the average sleeper weighing between 130 to 230 pounds. They typically have good support and are soft enough to conform to your curves without sinking too much.

7-10 (firm to very firm): Firm mattresses are the most supportive, but they typically do not conform well to the body’s curves. They can be a good choice for people who are heavy (230 pounds or more), or those with chronic pain.

What is Universal Comfort?

Some mattresses are described with the term universal comfort. Universal comfort describes mattresses that are believed to be comfortable for most sleepers in terms of firmness, support, and conformability.. Medium-firm mattresses with a rating between 5 to 7 on the firmness scale tend to be referred to as universal comfort mattresses.

How to Choose Your Ideal Mattress Firmness

As you decide which level of mattress firmness works best for you, there are a few things you should keep in mind. Factors including your weight and sleeping position are important to determining the right mattress firmness for you.

How much do you weigh?

In general, the more you weigh, the firmer your bed should be. With a soft mattress, heavier people will sink too far into the mattress to feel comfortable, while a firm mattress will not conform well enough to relieve pressure for lighter people.

  • Light (130 pounds or less): Soft to medium-firm mattresses (from 2-5) are the best choice for light people. A softer mattress will offer better conforming ability for this weight level.
  • Average (130 to 230 pounds): Medium-firm mattresses (from 4-6) are a good choice for average people. This level of firmness gives good support and conformability.
  • Heavy (230 pounds or more): Medium-firm to firm mattresses (from 6 to 9) are good for heavy people who will put more pressure on a mattress and may sink too deeply into too-soft mattresses.

What position do you sleep in?

Your sleep position also makes a difference in the ideal firmness for a mattress. In general, side sleepers do best with soft to medium mattresses, stomach sleepers with medium-firm mattresses, and back sleepers with medium-firm to firm mattresses.

  • Side: Side sleepers benefit from the greater conformability of soft to medium mattresses ranging from 2 to 6.
  • Back: Back sleepers do well with medium firm to firm mattresses (from 4 to 8), which distribute pressure evenly on the body.
  • Stomach: Stomach sleepers should look for medium-firm mattresses (from 4 to 6), which won’t sink too deeply like a soft mattress or put too much pressure like a firm mattress.
Scale Rating Softness/Firmness Characteristics Sleeping Position Ideal Weight
1 Very soft Deep sinking and contouring Side Light (130 pounds or less)
2-3 Soft Moderate contouring and sinking Side Light to average sleepers (less than 130 to 230 pounds)
4-6 Medium to Medium-firm Balanced firmness, support, and comformability Side, back, and stomach Average to heavy (130 to 230 oounds or more)
7-9 Firm Higher levels of firmness and support with less conformability Back Heavy (230 pounds or more)
10 Very firm Extremely hard, little to no conformability Back Heavy (230 pounds or more)

Other Considerations for Mattress Firmness

Don’t confuse firmness with support. Firmness and support aren’t the same thing. Support is how well a mattress relieves pressure and keeps your spine in alignment regardless of how soft or firm a mattress is, while firmness is how hard a mattress feels when you lie down on it.

Be very careful with soft mattresses. Most people that believe they like sleeping on a cloud really don’t. Though soft mattresses will offer the best conforming abilities, they are not comfortable for all sleepers. People of average to heavy weight will typically sink too deeply into a soft mattress to feel comfortable and well supported.

Medium firmness is best for most sleepers. Even though one size doesn’t always fit all, medium firmness (ranging from 6 to 7) is the best firmness level for most people (about 80 percent of sleepers).