Mattress Firmness Guide

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Finding a mattress that’s comfortable is easier when you know which firmness level suits your needs. This is why firmness is one of the most important factors to understand when mattress shopping. Beds range from very soft to very firm, and the firmness level you might initially gravitate towards may not be suitable for your sleeping style or body type. In this guide, we’re sharing what firmness is, why it matters, and how to determine the ideal firmness level for you.

What is Mattress Firmness?

Mattress firmness refers to a mattress’ comfort on initial touch, or how soft or firm the bed feels to an individual sleeper. Firmness is a subjective mattress quality. How a mattress feels to you will be dictated by your height, weight, gender, sleeping position, and personal preferences. 

Firmness matters in your mattress purchase for a few reasons. As a subjective quality, its primary importance is to allow you to enjoy the feel of the mattress you sleep on every night. Secondarily, the firmness setting doesn’t determine other important mattress qualities like airflow, contouring properties, durability, or odor potential, but it will impact them. 

Firmness vs. Support: What’s the Difference?

Firmness and support are often confused. It’s intuitive to think that a very firm mattress would offer good support since we associate words like solid, flat, and strong with the word ‘firm.’ These mattress qualities are not the same, though they have a mutually dependent relationship. 

In the world of mattresses, both soft and firm beds can offer excellent support or poor support. Firmness describes the uppermost layers that determine a bed’s comfort levels. Support describes the core and lower layers that determine how the mattress will encourage proper spinal alignment and relieve pressure. Firmness, as mentioned, is subjective. Does the mattress feel hard or soft to you? Support is objective. When you lie on a mattress, does your spine rest in its natural ‘S’ position or is it out of alignment?

How is Mattress Firmness Determined?

Mattresses are rated based on how they feel to the average sleeper. Manufacturers and mattress reviewers rely on either a 1 to 10 scale or descriptive terms that correlate with this scale. In general, 1 means “extra soft,” 10 means “extra firm,” and 5 or 6 means “medium.” 

Here’s a breakdown of firmness levels:
  • 1-2: Very soft
  • 3-4: Soft
  • 5-6: Medium
  • 6-7: Medium-firm
  • 8: Firm
  • 9-10: Very firm

What Mattress Firmness is the Best?

While the firmness that’s right for you is ultimately up to personal preference, there are several factors that commonly influence which level feels right to an individual. These considerations will help lead you toward a range of firmnesses that you’ll enjoy.

Sleep Position

It’s relatively easy to predict which firmness levels a sleeper will enjoy based on their sleeping position of choice. 

  • Side sleepers do well on soft mattresses, which offer thick comfort layers that aid in body-contouring properties. Side sleepers require contouring to avoid pains and aches at the shoulders and hips.
  • Stomach sleepers tend to sleep comfortably on firm mattresses. A firm mattress provides a flat sleeping surface for their hips and pelvis to rest on. Too much sinkage in this area, especially for individuals who carry weight in their midsections, will throw the spine out of alignment.
  • Back sleepers enjoy the benefit of sleeping well on almost any mattress. The weight of back sleepers’ bodies is evenly distributed, so they can feel great on a soft, medium, or firm mattress. 
  • If you switch positions throughout the night, a medium-firm mattress or “universal comfort” mattress, which we’ll cover later, could be a suitable option.


The larger you are, whether in body weight or height, the more downward pressure your body will exert on a mattress. Heavier individuals tend to experience medium and firm mattresses as soft, whereas lightweight individuals might experience traditionally soft mattresses as not soft enough.

If you’re an average weight, the commonly used firmness scale is a good indicator of how mattresses will feel to you. If you fall in the lightweight or heavyweight category, consider a mattress that is softer than average or firmer than average, respectively. For example, heavy people who want a medium-firm feel will likely find that a firm or very firm mattress feels medium-firm to their bodies. 


Firmer mattresses are easier to get out of since you won’t experience deep sinkage on impact. This is something to consider if you’re elderly, have physical limitations, or are heavy and sink deep.

Sleeping Partner

If your partner is larger, smaller, or has a different sleeping position than you, you might prefer different firmness levels. If that’s the case, a medium-firm feel is a nice catch-all option that tends to feel pretty comfortable to most people. 

What is Universal Comfort?

Universal comfort, or universal firmness, is a term applied to mattresses that are designed to meet the needs of the majority of sleepers. These tend to fall between 5 and 8 on the firmness scale, and most would describe them as having a medium or medium-firm feel. In recent years, many mattress manufacturers have started to carry at least one mattress that falls into this category. While the promise of universal satisfaction regardless of sleeping position, weight, gender, or age is appealing, you should always test a mattress described as “universally comfortable.” These mattresses aren’t necessarily a one-size-fits-all. Be sure to take advantage of the trial period, read reviews, and make sure it’s truly a balanced, comfortable feel you enjoy.


At the end of the day, the firmness level you choose is up to you. Consider your sleep position, body type, weight, and budget when making this decision. We always recommend purchasing a new mattress with a sleep trial so that you can try it in the comfort of your home for a few weeks.