March 2020

What’s inside my mattress? – Understanding the GSM of upholstery

GSM or Grams per Square Meter is the one thing mattress manufacturers do not want you to know when it comes to buying a new mattress. Once you do, you've got the upper hand in finding out exactly what's inside your mattress. We explain exactly why they hide this detail and how you can find out exactly what's in your potential new mattress. Helping save you time and not waste money when mattress shopping.

Updated 2020: Would you believe it if we told you that the majority of mattress retailers withhold information from you when selling beds. Information that is crucial in the design and construction of mattresses that all mattress retailers will have but decide not to share this with you the customer. This article lifts the covers on this murky practice and why you always need to ask ‘What’s the GSM of the fillings in this mattress?’.

Artisan Bespoke 003 logo
We always have and always will disclose the exact components and GSm’s of our mattresses. We explain why others won’t.

You may have never seen this number or reference when mattress shopping which goes to show just how secretive the mattress industry is. The finest examples of Quality Mattress manufacture like Savoir & Vispring always disclose the GSM of there mattresses as do we with our entire range. Let’s look a bit further about why you really need to know the GSM.

What is GSM in a mattress?

GSM stands for ‘Grams per square metre’ in upholstery terms. It refers to the actual weight of a particular upholstery component used within the mattress. It is a measurement used by all mattress manufacturers when purchasing upholstery and used as a basis to establish the quality of a particular mattress. It is the weight of a square metre of material and it does not matter what type (Wool, Polyester, Horsehair) or how deep or fluffy. How thin or how bouncy the actual weight of a metre of the material remains constant.

This constant measurement of mattress fillings is known as the GSM (grams per square meter) as it represented by a figure from 50gsm upwards. The higher the number the more of that fibre the mattress contains.

1200 gsm blended wool and cotton cross section
Without knowing the Grams Per Square Meter you have no idea if the mattress is a good buy or not

It is also the weight of the entire depth of various upholstery components used directly on top of the springs and this is known as the ‘combined upholstery weight GSM’.  This is the weight in One Square Metre of all upholstery used in your mattress. If you know this GSM figure – you would be able to tell which mattress is better than another without even lying on it.

Knowing the grams per square metre allows you to know whats inside any mattress
Knowing the grams per square metre allows you to know whats inside any mattress
Retailers want to keep this hidden so you can't compare value
Retailers want to keep this hidden so you can't compare value

Knowing the GSM allows you to work out the mattress quality

The reason that manufacturers and mattress retailers hide the GSM is that they don’t want you to be able to make side by side comparisons between bed brands and mattress models. With this key bit of information missing, it means you will struggle to be able to properly compare and choose a new mattress. This way salespeople in bed shops can push discounts, finance and other sales gimmicks at you. Wearing you down until you pick whichever bed you ‘think’ is best. Wouldn’t it be best if you actually ‘knew’ which bed gave you the most for your money?

Take wool as an example.

  • This comes in weights of 300 GSM / 600 GSM / 1200 GSM.
  • You see two mattresses advertised as having wool upholstery.
  • One has 1200 GSM wool as the upholstery. The other has just a miserly 300 GSM.
  • They are both selling at £500.

Unless you know which mattress has the 1200 GSM wool, you will never know which was the better-built mattress for the same price.

Bonded wool and cotton
Fibres come in a variety of GSMs so knowing how much you’re getting is essential

Is it really important to know GSM?

Absolutely it is. In fact, so important for you to know it is very rarely mentioned in any mattress description you will see in the store or on the internet. This is the one thing manufacturers do not want you to know or ask about, and they rarely divulge this to the retailer never mind the consumer. Even though retailers will have to have this information as this is the main way that you design a mattress. The GSM is not left to guesswork it is carefully planned based on the feel of the mattress and the quality level it is going to be sold at. So beware retailers that tell you they don’t know. It would be impossible for them to make a mattress without knowing the GSM of each filling.

Once you read the explanation below you will soon see that on the majority of mattress specifications and descriptions of a mattress from the majority of retailers this blatant omission becomes evident by its very absence.

What GSM should I look for in a mattress?

When looking for a new mattress you, quite rightly, want to get the most bang for your buck. Making sure when buying a new mattress that you’re choosing one with the most fillings. Significant mattress fillings will ensure your mattress lasts longer and doesn’t get as affected by settlement over time. Below is a table of roughly how much to expect in terms of overall total GSM for mattress price points. Obviously different fibres have different price points so it’s just a guide as to what you can expect.

Mattress PriceMin GSM AmountExample
£5001000gsmOrigins Comfort 1000
£7501200gsmOrigins Pocket 1500
£10001500gsm-2000gsmArtisan 1500
£12502000gsm-3000gsmArtisan Naturals
£15003000gsm-4000gsmArtisan Bespoke 004
£2000+3500gsm-6000gsmArtisan Sublime

We also have a ‘what to expect for your money’ table underneath. So you can see that for example, a £500 mattress is going to contain primarily synthetic fibres, whereas a £2000+ mattress should contain primarily natural fibres.

How much to spend on a double mattress?What can I expect for my money?
Under £500Will not get you much at best a 13.5 gauge open coil/cage sprung with a thin polyester layer or a solid foam mattress.
£500Entry level spunbond springs with some form of synthetic upholstery. Usually one sided mattresses.
£750The beginnings of a basic pocket springs unit with 800 – 1000 count. No substantial amount of filling other than foams and synthetic materials. Two sided models.
£1000Should get you away from most low ranges and into the mid-range pocket spring models.
£1250Should get you a decent pocket sprung mattress with some Natural Fibre content.
£1500Should get you many manufacturers mid-range models with Natural Fibres
£1500-£2000Should get you a Hand Made primarily Natural Fibre Quality Mattress
£2000+You should expect 100% Natural Fibres and Traditional Hand Made Construction Method.
£5000+A Bespoke Hand Made Sleep System, High-end Spring Units & Featuring the Worlds Most Luxurious Natural Fibres.
Finding out how much fibre is in your mattress is key to being able to compare its quality
Finding out how much fibre is in your mattress is key to being able to compare its quality
Vague descriptions should be further investigated or avoided
Vague descriptions should be further investigated or avoided

So what is mattress GSM in simple terms?

Let us look at a typical real-life example. This is a description and specification of a mattress sold by Dreams Flaxby Nature’s Finest 16500 DNAir Mattress (Jan 2020 £2,499 Kingsize).

The product description states:

‘Our Natures Finest 16500 mattress uses Egyptian cotton, a durable filling that helps to keep you fresh and cool during the night as the material wicks potential moisture away from the body giving you that extra comfort benefit. Egyptian cotton has longer and finer strands than ordinary cotton, giving it a superior and more luxurious feel. The Natures Finest DNAir 16500 also includes layers of wool and hemp sourced from farms in and around Yorkshire. Using wool gives the mattress a soft, springy and naturally supportive feel whilst also possessing anti-bacterial properties. Other layers include mohair, which has a slightly softer and smoother texture than wool but still provides great strength with a more luxurious and silky feel.’

Advertised Specifications:

Beds in a showroom
Mattress descriptions in retail stores are notoriously vague which is why you simply must ask the GSM contained

What you need to know to see where your money is going

We know that it contains 16,500 springs and given we already know that the maximum amount of springs in a kingsize mattress is 2,000 they must be using multiple layers of Micro or HD springs. However, the upholstery is the most interesting part and lack of detail on the fillings. The description states quite clearly “layers”  What exactly is the amount in these ‘layers’? 

The specification tells you that the key fillings are Egyptian cotton, Wool blended with Hemp and Mohair, but how you do you actually know that this is true? Don’t just take the above description as being what you ‘think’ you will be getting.

The above is all the information this particular retailer decides to give you. But remember, they are asking about £2,499 for this particular mattress so you should absolutely need to know where your money is going? We also know you should be expecting 3,000+ total GSM for a mattress like this.

How can I tell what is in a mattress?

The best way is to ask directly either the salesperson or get in touch with the brand directly to ask. Alternatively, we have over 200 mattress models in our Mattress Comparison tool where we have found out the GSM to save you the time. Click to view.

We’re going to show you with five questions how you can check what’s inside a mattress. Using the example above these are the questions we would pose to this particular retailer. This will explain in detail what you are up against.

1. What is the combined upholstery weight of the mattress?

The combined upholstery weight is the total weight of all the fillings used in a square metre of the mattress upholstery. If we take for granted that for this retail price you should be looking at around 3000GSM of premium upholstery this description tells you very little. In reality, it could be a paltry 1000GSM and you will have no recourse because you weren’t told otherwise. Sometimes a good way to check the GSM of a mattress is to find out the total weight of the mattress in a kingsize. If its only 35kg, for example, it’s going to be super light touch maybe 1000gsm however if its 75kg then it should contain roughly 3000-3500gsm.

2. Is there polyester in the mattress?

Polyester is amongst the cheapest mattress components you can get. Usually, given names like premium white fibre or anti-allergenic white fibre, it is still polyester and it is still cheap. If this component forms the bulk of the upholstery you are paying top whack for a cheap mattress. However, we don’t know for sure if there’s polyester in this mattress as although it has natural in the title there’s no reference to 100% Natural fibres. The minimum would be 300GSM and the likely maximum 1500GSM which is probably used in the pillowtop of this mattress to give it the loft it requires.

Pollyester 800G

3. What is the GSM of the Egyptian cotton?

Take note that on the description given, the Egyptian cottons GSM is missing. It is quite rare for cotton to be used as a stand-alone component (it is not fire retardant) and usually forms part of a blend. In this case, it is likely that the polyester/cotton is a component known as RPC (rebound poly cotton) not a bad component but not premium either. Egyptian cotton is super soft with high loft but also high compression. This means it flattens really quickly unless blended with another fibre to give it more rigidity in a mattress comfort layer. This comes in weights of 300GSM, 600GSM and multiples thereof. As no GSM is given you can be buying a paltry 300GSM or an acceptable 1200GSM. You don’t know!

4. What is the GSM of the Wool & Hemp blend?

Again, same story. There’s absolutely no detail given as to the GSM or blend of this fibre. Is this the top comfort layer or buried further into the mattress? Is this a 300gsm thin pad of a 2000gsm thicker layer? Also Wool & Hemp have two very different properties. Wool is incredibly soft with high loft whereas Hemp is a very flat firmer fibre with low loft usually used to firm up mattress upholstery. So they are in direct odds with each other.

1200 gsm of blended wool and cotton cross section
Knowing the Blend and GSM is essential to be able to compare. View our Wool mattresses here.

If you see the description of wool, silk and cashmere on a product description you can assume it is there to make the mattress look as though it is packed with premium components. However, without a gsm weight attached the actual weight could be so minimal it is worthless.

5. What is the GSM of the Mohair?

Mohair is a premium component and this is more than likely to be used as the spring insulator. The description is a little misleading as softer than Wool as usually Mohair in mattress construction is used as a firmer breathable layer in a mattress like in our Artisan Tailored Pocket 2000. Being part of a blend, say with pure new wool you will then have to know the ratio. Mohair is expensive and so don’t be surprised if the ratio of Mohair is as little as 5% of the entire GSM. The fact that it can legally be included within a product description has more value than the component itself.

1200 gsm Mohair layer
Click to find out more about Mohair mattresses

And that’s it. A little scratch on the surface which from a simple description and basic specification of a mattress that is retailing at £2499 or so opens up a complete minefield of questions and doubt. This is a classic example of why you are going to find purchasing a mattress so ridiculously hard, frustrating but completely unnecessary. If you can find out the GSM you’re in a far stronger position to choose the correct mattress for your needs.

There is no legal requirement for a manufacturer or retailer to divulge the contents by weight to you but that does not make it right. Looking at the description above even we cannot tell you what the weight and breakdown of the upholstery layers are - they are complete unknowns and without you knowing what these are it becomes quite impossible for you to do any kind of comparison to other models. And this is the sole reason why this shameless practise is carried on.
There is no legal requirement for a manufacturer or retailer to divulge the contents

How much do mattress natural fibres cost?

We’ve put together a handy table below to help you get an idea of just how expensive certain fibres are. This will help you work out whether that mattress ‘deal’ you’ve seen can really contain the ‘vague’ natural fibres it lists. Keeping you one step ahead of the shady tactics.

Natural fibreCost / Availability
AlpacaVery expensive (low supply chain)
Bamboo Average price (good supply chain)
CamelVery expensive (low supply chain)
CashmereExpensive (good supply chain)
Cattle HairAverage price (good supply chain)
CoirAverage price (good supply chain)
CottonVery expensive (good supply chain)
FlaxAverage price (good supply chain)
HempAverage price (good supply chain)
Horsetail Very expensive (low supply chain)
Horsehair Less expensive (good supply chain)
MohairExpensive (low supply chain)
SilkVery expensive (low supply chain)
VicunaVery Expensive (Most expensive natural fibre in the world)
WoolModerate to expensive (good supply chain)
How to compare mattresses based on GSM
We show you exactly how to work out a comparison

You may be thinking that all of this is completely mind-bending and complicated it is initially but it is absolutely essential you understand it otherwise, you will be at the complete and utter mercy of the manufacturer and retailer. The moral to all of this is not to take any description at face value. The least you need to know is the ‘grams per square metre’ of all components used within the mattress. If a mattress description tells you it is filled with ‘luxurious horsehair’ or has ‘sumptuously soft silk’ you need to be asking but how much?

This is just the starter post on understanding what it will take to find your perfect mattress. As with the Dreams Lincoln example above you have to know how to do comparisons between different models to see which is giving you the best mattress for your money. For us, it has now become second nature, and we know this will be a considered exercise for you. There is absolutely no need to panic!

By finding out the GSM of the mattress you can quickly compare them side by side like the example here.

Artisan Bespoke 004 Vi Spring Regal Superb
1 1200gsm Blended British Fleece Wool and Cotton 900gsm Blended real Shetland Isle Fleece Wool and Cotton
2 Hairproof Cambric Cover Hairproof Cambric Cover
3 200gsm Soft Bamboo NA
4 1200gsm Pure Horsetail 1200gsm long stranded Horsetail blended with British Fleece Wool
5 1000gsm Bonded British Fleece Wool and Cotton 1000gsm Bonded British Fleece Wool and Cotton
6 1600 Calico encased Pocket Springs [ 49mm ] [1.28mm] 1720 Calico encased Pocket Springs [48mm ] [1.28mm]
TOTAL GSM 3600 3100
Rated Excellent Trustpilot
You should know exactly whats in your mattress

Once you understand what to look for you will be skimming through descriptions like a demon and quite enjoy spotting the misleading and dubious specifications you come up against. There really should be no reason why you should go to these extraordinarily long lengths having to play Sherlock Holmes and phoning manufacturers to ask the necessary detail on upholstery before you hand over hundreds or even thousands of pounds for your mattress. To be honest, it’s absolutely disgraceful that you will have to do this to compare.

The GSM value of upholstery is the one thing 99% of ALL manufacturers do not want you to know.

We hope that manufacturers and retailers will eventually tire of the calls and questions and list their products the same way as food manufacturers do with a completely itemised summary showing component and weight.

If you want to find out what’s inside a mattress why not give our expert team a call on 0161 437 4419 or drop us a message below. You can also use our Mattress Comparison tool which details the GSM of over 200 retail models.

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