What are HD or Micro Springs?

In the race to increase mattress spring counts, many manufacturers are using micro or HD (High definition) springs. Do you really need 8,000 springs in a mattress and how on earth do they fit them all in? If you’re confused like most about micro springs then this article should help clear up the confusion!

What is a HD Micro Spring?

HD (High Density) Pocket Springs or Micro springs are small pocket springs that many bed manufacturers use to vastly increase their mattress spring count. You can fit in thousands of these tiny springs in a mattress so you can sell a model as having 6000, 8000 or even 10,000 springs.

The manufacturers advise the benefits of micro springs along the following sales pitches;

  • Micro adjustments to pressure when you lie on your mattress
  • A more advanced progressive comfort

Quite frankly you should never need this amount of springs. Let us explain why.

What are micro springs used for?

Micro springs or HD springs where created to allow additional ‘support layers’ to be used in mattresses. Originally this would be for very small mattresses, such as cot mattresses where this would be the only spring unit and could fit in a far smaller mattress. There’s only so much innovation that you can craft into a wire spring, such as our Vanadium coated calico pocket springs which are more resistant to rust and highly responsive for their tensile strength (more on what that actually means here). Given there’s only so much you can do to improve the humble springs design, manufacturers have started competing for the highest spring counts. It used to be the shape of springs, whether conical or cylindrical now its spring counts.

Base pads use smaller springs – our Legacy model uses half sized Vanadium Calico Pocket Springs – never a synthetic Micro spring

Now HD springs and small springs are useful for things like mattress base pads (see our Worlds Finest Legacy as an example of a high-end base pad) or deep handmade toppers. In reality, there are only a few legitimate uses for them. They do allow manufacturers to boast ridiculous spring counts in a mattress though.

Micro springs compress really quickly, which is probably where the benefit of ‘micro-adjustments’ comes from, as they are only about an inch in depth. So when using them as a support layer you need layer after layer of them to get any meaningful support. You need a lot more of them to do the same job as a Calico pocket spring.

mattress natural fibres
Upholstery layers should not be sacrificed for ‘Micro’ or HD springs in our opinion

This means that you’re also losing valuable space in the mattress where natural fibres or other upholstery layers could be used. Mattresses can only be made so deep so the more springs layers, the less upholstery you can put in.

Do Micro Springs make a mattress more expensive?

Given the fact you may need 3 times the amount of these springs in your mattress the answer most of the time is yes. Though it depends on how they are made, what they are coated in, usually synthetic polyester and how many the mattress contains. You would think that the reduction in upholstery would reduce the cost of the mattress but it seems not. You’re getting less upholstery and paying more for it! The money spent on Micro springs would be better utilised in the comfort layers of our mattress.

What’s the difference between a Micro spring and a Pocket Spring?

You can see an image of an example HD / micro spring below compared to a Vanadium Calico encased Pocket Spring. There is no real comparison as the HD spring is coated in a spun bond synthetic cover then glued together and about a 3rd of the size. The Calico spring is far more breathable and is stitched together without the need for synthetics.

Micro springs are about a 3rd of the size of a regular pocket spring usually spun bond in synthetic material
Calico encased pocket springs are used only by High-End mattress manufacturers

Do I need HD springs in my mattress?

HD springs also have the unfortunate implication of increasing the amount of wire and metal in your bed. A quality Calico Pocket Spring will provide all the necessary support and progression for sleepers allowing them to turn and the mattress to respond to them. By reducing the size of the springs manufacturers have overengineered the bed and you then require even more springs to counteract the compression of these. It also means there are great amounts of wire taking up valuable space compared to breathable fibres.

As for the micro adjustments, a high-end calico pocket spring unit is far more suitable than lots of rows of tiny springs. They provide a far more consistent sleep surface allowing for layer and layers of deep upholstery layers rather than excess metal. The advanced progressive comfort is a bit misleading as it refers to the spring unit being the only part of your sleep comfort when we know the upholstery layers are just as important.


You’re far better off spending your money on increased natural fillings rather than synthetic spun bond HD pocket springs. Want to get free tailored advice on your new mattress? Why not get in touch with our small expert team on 0161 437 4419 or email [email protected]