Last updated: August 2026
Open coil and pocket sprung are the two ways a mattress can be built around steel springs. One joins every spring into a single frame, the other lets each spring work on its own, and that decides how the bed feels, how long it lasts and what it costs.
Quick answer: An open coil mattress is best for a guest room, a child's bed or a tight budget, because it is cheap, light and firm, but every spring moves with its neighbours so couples feel each other move and the middle sags first. A pocket sprung mattress is best for anyone sharing a bed or sleeping on it every night, because each spring responds separately for zoned support and far less partner disturbance. A hybrid adds foam on top of pocket springs: the REM-Fit Pocket 1000 pairs 1000 full-height pocket springs with open-cell memory foam at a medium-firm 7 out of 10, with a 100-night trial and a 15-year guarantee.
What is the difference between open coil and pocket sprung?
The difference is whether the springs are connected. In an open coil mattress they are wired together into one unit, while in a pocket sprung mattress each spring sits in its own fabric pocket and moves independently.
An open coil mattress is a mattress supported by rows of hourglass-shaped springs joined to each other by a helical wire, with a rod around the edge for strength. It is also called Bonnell, cage sprung or standard sprung. The Sleep Foundation puts a typical count at 400 to 600 springs, and because they are linked, pressure on one spring pulls on the springs around it.
A pocket sprung mattress is a mattress supported by hundreds of individual springs, each sewn into its own fabric pocket, so each one compresses only under the weight directly above it. UK spring counts are quoted for a king size mattress. Around 1000 is the standard for a full-height pocket spring unit, while counts of 2000 and above usually come from a second layer of springs or smaller springs packed more tightly.
| Spec | Open coil | Pocket sprung | REM-Fit Pocket 1000 (hybrid) |
|---|---|---|---|
| Mattress type | Connected spring unit (Bonnell) | Individually pocketed springs | Pocket springs plus memory foam |
| Springs | Typically 400 to 600, wired together | 800 to 3,000+ (king size), independent | 1000 full-height pocket springs |
| Foam | Thin foam or fibre pad | Foam, fibre, wool or latex comfort layer | Open-cell memory foam comfort layer |
| Firmness (out of 10) | Usually 7 to 9, one tension across the bed | Full range, often zoned | 7 (medium-firm), multi-zoned |
| Height | Typically 18 to 25 cm | Typically 22 to 30 cm | 20 cm |
| Motion isolation | Poor, the whole surface moves | Good | Good, springs move independently |
| Edge support | Border rod | Varies, best with encapsulated edges | Reinforced edge, no roll-off |
| Trial length | Varies by brand | Varies by brand | 100 nights (200 with a protector) |
| Guarantee | Varies by brand | Varies by brand | 15 years |
| Delivery | Usually flat | Flat or rolled | Free UK delivery in 2 to 5 days |
| Made in | Varies | Varies | UK |
| Key award | Depends on model | Depends on model | Good Housekeeping Winner 2026 |
Who should buy an open coil mattress?
Buy open coil for a bed that is used occasionally, for a growing child, or when the budget will not stretch to pocket springs. It is the cheapest way to put a sprung mattress on a bed frame.
The connected frame gives open coil a firm, bouncy feel that some sleepers like, and the border rod keeps the edges stable. The unit is light, so the mattress is easy to turn and to carry up stairs, and most open coil mattresses can be flipped as well as rotated to spread the wear.
The weaknesses all come from the springs being joined. When one person turns over, the whole surface reacts, so a partner feels it. Two people of different weights tend to roll towards the middle, and because the centre takes the most load, the Sleep Foundation notes that this design is prone to sagging in the centre.
Open coil also offers one tension across the whole bed, with no zoning for the hips or shoulders. For a guest bed slept on a few nights a month, none of that matters much; for a bed you share every night, it does.
Who should buy a pocket sprung mattress?
Buy pocket sprung if you share a bed, sleep on it every night, or have a partner of a noticeably different weight. Independent springs solve the three biggest complaints about open coil.
Because each spring compresses on its own, a pocket sprung mattress follows the shape of the person on it. Heavier areas like the hips sink a little further while lighter areas stay supported, and the mattress can be zoned so the springs under the shoulders are softer than those under the lower back. The Sleep Charity's advice is that a mattress too soft makes you slouch while one too firm presses on the hips and shoulders, and zoning is how pocket springs steer between the two.
Partner disturbance drops sharply, and so does noise, because there is no wire frame to creak. The pocket sprung design also spreads the load across many small springs rather than concentrating it on a few linked ones, which is why it holds its shape for longer.
The trade-offs are price and weight. Pocket springs cost more to make, so entry-level pocket sprung mattresses start where mid-range open coil finishes, and the mattress is heavier to turn. A cheap one with a thin comfort layer can also feel as hard as open coil at the shoulders, and our guide to the best pocket spring mattresses in the UK explains what separates a good one from a cheap one.
Is open coil or pocket sprung better for your back?
Pocket sprung is the better choice for back support, because it keeps the spine level in more sleeping positions and does not develop a dip in the middle as quickly. Open coil can support a back well when new, but at a single firm tension that does not suit every sleeper.
The firmness matters as much as the spring type. A randomised trial of 313 adults with chronic low back pain, published in The Lancet in 2003, found that a medium-firm mattress reduced pain in bed and disability more than a firm one over 90 days. Most open coil mattresses sit at the firmer end, while pocket springs come in every tension, which is why a medium-firm pocket sprung mattress is the usual recommendation.
If your back pain is persistent, see a GP before you buy a mattress to fix it.
Where REM-Fit fits
Every one of the REM-Fit hybrid mattresses is pocket sprung, so the choice here is between open coil and a pocket sprung hybrid. A hybrid mattress is a mattress that combines a pocket spring base with one or more foam comfort layers, which fixes the thin-comfort-layer problem that cheap pocket sprung and open coil mattresses share.
The like-for-like against an open coil or entry-level pocket sprung mattress is the Pocket 1000. It uses 1000 full-height pocket springs running the full 20 cm depth of the mattress, an open-cell memory foam comfort layer, multi-zoned support and reinforced edges. It is medium-firm at 7 out of 10, made in the UK and was a Good Housekeeping Winner in 2026.
REM-Fit Pocket 1000 Hybrid Mattress
1000 full-height pocket springs with an open-cell memory foam top: independent support for couples, without the hard feel of a thin comfort layer.
Shop the Pocket 1000✓ 100-night trial (200 with a protector)✓ 15-year guarantee✓ Free UK delivery✓ 0% finance
If you want a higher spring count, the 3000 Supreme (medium, 6 out of 10) and the 4000 Ortho Elite (firm, 9 out of 10) use a dual-layer pocket spring system, with the second layer adding stability and a more progressive feel. Both are 25 cm deep and rated for sleepers up to 20 stone. The hybrid mattress guide explains how the layers work together.
Open coil vs pocket sprung: which is better value?
Open coil is cheaper to buy and pocket sprung is cheaper to own, because it lasts longer before it dips. Which is better value depends on how many nights the mattress will be slept on.
For a guest room, an open coil mattress used a few nights a month can serve for years, and pocket springs would be performance nobody uses. For a bed slept on every night, the central sag that open coil develops tends to arrive well before the mattress wears out, and that is when most people replace it.
When comparing pocket sprung mattresses against each other, look past the spring count to the size it is quoted for, the depth of the comfort layer, whether the edges are reinforced, and the length of the trial and guarantee. Our guide on how often to replace a mattress lists the signs that yours has reached the end.
Open coil vs pocket sprung FAQs
Last updated: August 2026
Which is better, open coil or pocket sprung?
Pocket sprung is better for everyday use and for couples, because independent springs give zoned support, less partner disturbance and a longer life. Open coil is better only where cost or occasional use matters more, such as a guest bed or a child's first full-size mattress.
Are pocket sprung mattresses the best?
Pocket springs are the best spring support system, but the mattress as a whole depends on what sits on top of them. A pocket sprung mattress with a thin comfort layer can feel hard, which is why hybrids add memory foam above the springs for pressure relief.
What are the common problems with pocket sprung mattresses?
The usual complaints are a hard feel from a thin comfort layer, weight that makes the mattress awkward to turn, and spring counts that mislead because they are quoted for different sizes. Very cheap pocket sprung mattresses can also use short springs that dip within a couple of years.
What are the disadvantages of an open coil mattress?
Open coil mattresses transfer movement across the whole surface, so partners disturb each other, and couples of different weights roll towards the middle. They also sag in the centre sooner than pocket springs and come in one tension with no zoning.
Is a 2000 or 4000 pocket sprung mattress better?
More springs are only better if they are full-height springs in the same size mattress. A 4000 count usually means two layers of springs, which gives a more stable and progressive feel than a single 2000 layer, but a well-made 1000 spring mattress will outperform a badly made 4000. Compare the depth and the comfort layer, not just the number.
Is an open coil mattress good for your back?
An open coil mattress can support a healthy back when it is new, but it offers one firm tension across the bed and develops a central dip over time, both of which can tip the spine out of line. Medium-firm pocket springs are the safer choice for anyone with back pain.
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Sources: Sleep Foundation, Mattress Coil Types; The Sleep Charity, Sleep Environment; Kovacs FM et al., The Lancet, 2003; REM-Fit product specifications, August 2026.
