What is Mattress Tension?

We have utilised our mattress knowledge and expertise to bring you a guide full of everything you would need to know about mattress tension.

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Mattress Tension

Mattress tension is one of the main considerations to make when choosing your new mattress.

The tension, or firmness, rating relates to whether the mattress is soft, firm, or something in the middle. There are a vast quantity of options out there to choose from, and without context they can be a little confusing. Choosing the right rating is important to getting a pain-free, comfortable sleep.

Luckily, here at Winston’s beds we’ve got you covered. With this guide exploring mattress tensions from the buyer perspective and assessing why spring tension is key to taking home the perfect mattress.

Why is mattress tension so important?

Mattress tension is important as it impacts the overall sleeping experience.

In short, the mattress tension determines the levels of comfort and support you receive, often meaning the difference between a soft mattress with no support and one which is rigid in build and feels extra firm.

More often than not, we see buyers choosing their mattress based only on the spring tension, under the assumption that this will give them the ‘true feel’ of the mattress. This is completely wrong. What creates and dictates the feel of the mattress is the fibres on top of the springs, the spring tension, and your body weight.

Of course, it doesn’t help that retailers are so bad at describing mattress firmness, with them often confusing comfort and spring tension and advertising the wrong thing.

There has to be a better way, right?

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What mattress firmness should I choose?

Choosing mattress firmness boils down to personal sleeping requirements.

Unfortunately, it is a little more complicated than saying “soft, medium or firm”. In the mattress industry, there isn’t actually a precise or global definition of what these indicators mean.

Sliding scales and ratings are rife, but with no continuity around what any of it means, purchase can end up being more of a guess than a precise selection. This guide is there to help cut out the guess work.

But why does this confusion exist? It is because retailers are using spring tension alone to dictate the firmness of a mattress. And this is wrong. Mattress firmness ratings are based on the upholstery layers and spring tension.

Along with the user’s body weight. For example if you’re looking for a medium firm mattress, you need to look at the right upholstery, as well as the spring tension and your own body weight in order to work out the correct mattress tension.

I know what you’re thinking – how do you do this yourself, and more importantly, why do you have to?

The best way to find your perfect mattress tension

The best way to find your perfect mattress tension is broken down into two key aspects of selection:

  • Identify what spring tension your bodyweight requires
  • Pick the comfort layers (mattress fillings) based on how they will feel

This may sound simple. But you will likely find that most retailers will keep much of this information from you, preferring to guide you towards the spring tension as the comfort rating.

If you follow these two steps, you’ll be able to achieve the desired mattress tension for you. Remember, the spring tension needs to be based on your bodyweight, not by how comfortable it feels to touch.

What spring tension should I choose

Choosing spring tension can vary from person to person.

There are a number of factors, although bodyweight is the most important, alongside price point. If your partner requires a different spring tension, there are split tension or zip and link options available.

Should you be only considering the ‘feel’ of the mattress, however, you’re doing it wrong. As such, a soft spring mattress doesn’t necessarily result in a soft bed. As mentioned, there are other factors to bear in mind.

If you are on a budget and would prefer an entry-level mattress, then it is worth noting that there is generally only one spring tension available.

This is often a 1.4mm gauge wire which is a medium firmness. This suits the largest number of sleepers as it is set in the middle and more people are likely to fall somewhere into this medium bracket.

Spring tensions are often broken down into soft, medium, and firm and, as mentioned, this can be a touch confusing for the uninitiated. Bodyweight is the most important thing to consider when choosing the right spring tension for you.

As such, the first question you should be asking yourself when deciding the right tensions is which spring gauge matches my body weight?

It is by answering these questions that you can determine the exact amount of support you will need.

In a high-end mattress, you may find a wider selection of spring tensions as shown below:

Spring Tension Wire Diameter (Gauge) Weight Range
Soft 1.2mm Up to 10 stone
Medium 1.4mm 10 to 16 stone
Firm 1.6mm 16 to 18 stone
Extra Firm 1.8mm 18 stone plus


Matching Body Weight To Mattress Tension

Your weight actually plays an important part in making sure you end up with the right mattress.

If you don’t take your weight into consideration, then you will find yourself guessing the best mattress tension you need, something which many retailers will avoid making clear.

By means of a very simple explanation – a light person will find an orthopaedic mattress rock hard, whereas a heavier person may find it is just right in terms of comfort. So, what kind of mattress would be best for a heavier person who is asking for a firm mattress?

Here at Winston’s, we know exactly which type of mattress would be suitable and unsuitable for a buyer weighing 18 stone. And we see it as our responsibility to make sure that you get the right mattress for your needs.

After all, we know which materials more durable, and which spring type are the most supportive. We also know whether a particular mattress would be better with an extra layer of filling. Or if something needs changing.

More than that, we know it shouldn’t fall to you to know all these things when you buy a mattress. You need to be able to trust your retailer.

Other Considerations:

  • Mattress tension is relative to the size of the mattress i.e. a single mattress will be firmer than a double mattress and a lot firmer than a king size.This is because the bigger the span of the mattress, the softer it will feel. Also, because you had a specific spring tension in a previous mattress it does not mean it will translate to your new mattress if you are upgrading or downsizing.
  • The fabric will also have an impact on the mattress tension. Mattresses that have a top layer of latex or foam will at most times have a soft knitted fabric on the sleeping surface. However, a polyester filled mattress will have a woven fabric on the sleeping surface of the mattress. A knitted fabric is much softer, but the woven fabric is far more breathable and hardwearing.

Mattress firmness vs. support

The mattress and bedding industry is rife with confusing buzzwords and slogans.

And the most complex is the perception of firmness and support. Often, these two words are used by retailers and buyers as one and the same – this has to stop.

Firmness and support are completely different and have very distinct meanings. Which must be acknowledged if you hope to end up with a quality mattress with the perfect finish for you.

The support unit of your mattress is always dictated by your weight, determining the distribution of weight you receive while sleeping. This is because spring units are manufactured with specific weight tolerances in mind. They are designed to take a certain amount of weight to compress and extend correctly.

If you end up with a spring unit which is not designed to take your body weight, you’re going to end up with either a firmer spring than you need (in which case it won’t compress as it should) or with too soft a spring (meaning it will compress too far). Both issues that will prevent the mattress from supporting you.

It is key that you understand the weight limit that can be applied to the spring in any given mattress.

Here at Winston’s Beds, our soft springs will accommodate anyone up to 10 stone.

Our medium springs will accommodate any user between 10 stone and 16 stone, the firm spring is perfect for anyone between 16 and 18 stone and our extra firm spring is for anyone 18 stone plus.

Don’t be afraid to ask the mattress retailer what the spring tolerance is.

As every manufacturer makes their mattresses differently, there is nothing wrong with asking the retailer what the weight bracket is for each tension. For example, at Winston’s Beds you can expect to receive the following information:

Spring Tension Weight Range
Soft Up to 10 stone
Medium 10 to 16 stone
Firm 16 to 18 stone
Extra Firm 18 stone plus


Using your mattress filling for comfort

Following the spring selection, the next thing you need to consider is how the upholstery layers of the mattress can and will affect the firmness and comfort.

One way to look at this is with a basic comparison:

Imagine two medium tension spring mattresses, suitable for a 13 stone user. The spring unit is identical, but we decide to top each one with a different upholstery layer. One ends up with a medium tension feel, while the other is much softer. This is how important the upholstery is.

  • Foam upholstery provides a much firmer feel than wool or cotton, which provides a very soft finish.
  • Horsehair will provide a very firm feel.
  • Alpaca fibre and bamboo can provide some of the softest finishes.

While the spring unit goes by your weight. The upholstery is what provides that final layer of comfort.

Upholstery Layer Fibre Type How Will It Feel?
White fibre Synthetic Soft/medium/firm
Memory foam Synthetic Medium/firm
Polycotton Synthetic/natural blend Soft/medium
Pure wool Natural Soft/medium
Pure cotton Natural Soft
Horsehair Natural Medium
Mohair Natural Medium/Firm
Hemp Natural Medium
Latex Natural Medium/Firm
Coir Natural Firm
Flax Natural Firm
Cashmere Natural Firm
Bamboo Natural Soft
Horsehair Natural Firm
Alpaca Natural Soft
Vicuna Natural Soft

Frequently Asked Questions

The softest mattresses tend to be made using the softest natural fillings, offering little in terms of support, but maximum comfort and softness. These include wool, alpaca, cotton, mohair, and bamboo. Though the finish with these fibres is often so soft that they are layered with other fibres, to firm them up a little and maximise support.
Medium mattresses are the most popular as they cover everything between the soft and the firm. Medium is, as ever, the all-rounder with the most fans, and is often the best option for those who are not sure what to go for.

Medium mattresses used a blend of the softer fibres with the firmer and more resilient ones, providing support but also comfort.
Firm mattresses are the most robust. Using fibres such as horsetail, flax, polycotton, reflex foam and dense layering, providing more support to the body than the softer fillings. Buyers should be aware that a firm feel mattress can sometimes lead to back ache, if you are not used to it. And that a medium support mattress may be the better option for those who are use to a softer finish, but are looking for more support.
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The most important point to reiterate here is that to establish whether a bed is soft, medium or firm, you need to pay attention to the upholstery layers and the spring tension.

Spring tension must be based on your body weight. And mattress fillings should then be used to establish how firm the mattress will feel. Of course, most retailers won’t tell you this, preferring instead to go for the quick sale, rather than go into depth about what you should be looking for.

For a retailer you can trust, built on transparency and a commitment to our customers. Try Winston’s Beds for all your mattress needs.

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Published: 11th November 2020 (Updated: 12th August 2022) | Graham