Available 
Sleepeezee Luxury Ortho 1600 Pocket Mattress
from £381-£727.
£381-£727
Sizes tracked: Single, Small Double, Double, King Size, Super King
Sleep guide
How to choose the right mattress firmness for your sleep position
A sleep-position-first guide to mattress firmness, using three Mattress Online pocket sprung examples to compare feel, support, sizes and value.
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Last verified: 2026-10-01
Why sleep position changes mattress feel
Sleep position is the easiest starting point, but it should only guide the shortlist, not make the decision for you. Side sleepers usually need more cushioning around the shoulder and hip, while back and front sleepers tend to look for steadier support and more even weight distribution. Mattress firmness labels are not standard across the market, so a firm tag on one retailer page may not feel identical to a firm tag elsewhere.
Best firmness for side sleepers
Side sleepers often do better with a medium or medium-firm feel that allows enough give at the shoulder and hip without letting the body sink too far. On this page, the Sleepeezee Luxury Ortho 1600 Pocket Mattress is listed as firm at £381-£727, the Sleepeezee Classic Ortho 800 Pocket Mattress is shown as medium to firm at £254-£468, and the SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress is listed as firm at £478-£568. That spread is useful because it shows how the same broad firmness family can still feel quite different once you factor in fibre fillings versus gel foam comfort layers.
Best firmness for back sleepers
Back sleepers usually want support that helps the mattress feel even across the body rather than overly soft at one end and firm at the other. Pocket sprung builds are a good place to start because they are designed to respond to body weight across the surface, but the comfort layer still changes the feel a lot. Before deciding, check the mattress size options and base fit as well as the firmness label, because a mattress that suits your position still has to work with your bed frame and room.
Best firmness for front sleepers
Front sleepers usually start with firmer support because a mattress that lets the hips dip too far can feel awkward and less balanced. The three Mattress Online examples all lean firm, but they do not feel identical: both Sleepeezee models use pocket springs with soft white fibre fillings, while the SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress pairs pocket springs with gel foam comfort fillings. The Classic Ortho 800 is especially worth a close look here because its live page says medium to firm, which is a reminder to compare the wording on the current product page rather than relying on a label elsewhere.
What the shortlist says about price, build and terms
The comparison set runs from £254-£468 for the Sleepeezee Classic Ortho 800 Pocket Mattress up to £381-£727 for the Sleepeezee Luxury Ortho 1600 Pocket Mattress, with the SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress at £478-£568. All three show a 100-night comfort trial, but the long-term cover differs: the Classic Ortho 800 has a 5-year guarantee, while the Luxury Ortho 1600 and Space 4000 both show 10-year cover on their product pages. review details are positive but uneven, with 5.0/5 from 6 reviews for the Luxury Ortho 1600, 4.5/5 from 238 reviews for the Classic Ortho 800 and 4.7/5 from 38 reviews for the Space 4000, so those scores are better treated as soft context than a final verdict.
How to narrow the choice before you buy
If budget matters most, the Sleepeezee Classic Ortho 800 gives the lowest starting price and the broadest five-size spread, making it a practical reference point for smaller budgets and standard UK bed sizes. If you want a longer cover period and a firmer reference with the same five-size coverage, the Sleepeezee Luxury Ortho 1600 is the clearer comparison point, while the SleepSoul Space 4000 is the most different-feeling option because its comfort layer uses gel foam and it only comes in three sizes: Double, King Size and Super King. Before ordering, check mattress depth, bedding fit and base compatibility on the live retailer page, because those practical details can matter as much as the firmness label when you are choosing for a specific room or frame.
Mattresses to use as comparison examples
Available 
Sleepeezee Classic Ortho 800 Pocket Mattress
from £254-£468.
£254-£468
Sizes tracked: Single, Small Double, Double, King Size, Super King
Available 
SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress
from £478-£568.
£478-£568
Sizes tracked: Double, King Size, Super King
Retailer details used
Last checked 2026-10-01. The source list below is included to help you check the details behind the comparison. Always confirm the latest price, delivery cost, stock status and product details with the retailer before buying.
- Sleepeezee Luxury Ortho 1600 Pocket Mattress | MattressOnlineproduct-page evidence for Sleepeezee Luxury Ortho 1600 Pocket Mattress
- Sleepeezee Classic Ortho 800 Pocket Mattress | MattressOnlineproduct-page evidence for Sleepeezee Classic Ortho 800 Pocket Mattress
- SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress | MattressOnlineproduct-page evidence for SleepSoul Space 4000 Pocket Orthopaedic Gel Mattress
- What mattress firmness is right for me? - MattressOnlineNon-standard firmness labels and individual preferences
- The best mattresses for each sleeping position - MattressOnlineComparable educational guide structure and qualified retailer selection advice
- MattressOnline 100-night comfort trialExchange eligibility and fee, distinct from a refund promise
Helpful next reads
Use these related mattresses guides and reviews to turn the advice into a practical shortlist.
Firmness questions
Do side sleepers always need a soft mattress?
No. Many side sleepers find that a medium or medium-firm feel works better than a very soft mattress because it still cushions the shoulder and hip without making the body sink too deeply. On Mattress Online, the Sleepeezee Classic Ortho 800 is listed as medium to firm, which may suit shoppers who want support with a little more give.
Is a firm mattress best for back sleepers?
Often, but not always. Back sleepers usually look for even support, yet the comfort layer still matters because a mattress that feels too hard can be uncomfortable even if the support system is sound. The three examples here all use pocket springs, but the Sleepeezee models use soft white fibre fillings while the SleepSoul Space 4000 uses gel foam comfort fillings.
Why do firm labels vary between retailers?
Firmness labels are not standardized across the market, so two mattresses marked firm can still feel different once you compare the spring system, comfort layer and depth. That is why it helps to look at the product title, the live firmness wording, size range and guarantee terms together rather than relying on the label alone.