Before You Buy a Mattress (UK Checklist)
Published 2026-08-03. Last updated 2026-08-28. Desk research by Kaiser Khan — we have not product-tested before you buy a mattress UK. This is not a shop review and not medical advice.
In short
Before you buy a mattress in the UK, lock size in centimetres, pick a build type, match support to body weight, then tune top feel for how you sleep. Check the base and slat gaps, trial and warranty small print, delivery access and old-mattress disposal. Soft, medium and firm labels are not a shared scale across shops.
- Size
- Centimetres first
- Warranty risk
- Base next
- Two tracks
- Trial ≠ warranty
A UK King is 150 × 200 cm. A Double is 135 × 190 cm.
Wide slats or a hammocking foundation are a usual void.
Comfort dislike is usually a trial issue, not a fault claim.
About 5 minutes to read
What materials go into this mattress?
Typical builds use pocket springs, open coil springs, memory foam, latex, hybrid stacks. Exact stacks vary by model. Read the spec, not the shop slogan.
- pocket springs
- open coil springs
- memory foam
- latex
- hybrid stacks
How long does this mattress typically last?
A typical range is 6– 10 years. Body weight, base support and rotation change that. It is not a warranty promise.
6– 10 years
What should I check before I buy a mattress in the UK?
Lock size in centimetres. Check the base and the stairs. Then pick build type and support for body weight. Then pick top feel for how you sleep. Then read trial and warranty small print. Then plan disposal of the old mattress. Soft, medium and firm labels are not a shared scale.
Work top to bottom. Skipping size or base is the usual expensive mistake. This is a checklist, not a ranking. We have not tested products for you.
1. What size do I need, in centimetres?
Use UK standard bed sizes. A Double is 135 × 190 cm. A King is 150 × 200 cm. A Super King is 180 × 200 cm. Names fail when frames or sheets come from the EU or US. See UK vs EU sizes.
2. Will it fit the room and the stairs?
Measure walkways and the path upstairs. A mattress that cannot turn on the landing is still the wrong mattress. See bed footprint and access and delivery and disposal.
Rolled “bed in a box” products change the packed size. They do not change the finished centimetres. See bed in a box.
3. Is the bed base allowed by the warranty?
The base can void a warranty if slat gaps or foundations are wrong. Foam-heavy mattresses often need a firm platform. Start with how to choose a bed base and mattress–base compatibility.
4. Which build type?
Pocket sprung, hybrid, foam, latex or open coil. See mattress types and how to choose a mattress. Pick the mechanism before you pick a fabric story.
5. Does support match body weight?
For spring beds, match spring tension to weight. For foam, read density and ILD. Two people with very different weights may need zip-and-link — couples.
6. Does the top feel match how you sleep?
Side, back and stomach sleepers need different surface give. See firmness and sleep position plus the side, back and stomach guides. This is not medical advice.
7. What quality signals beat marketing words?
Ask about upholstery depth and GSM, turnability, edge support and what price usually buys in construction terms. Ignore “orthopaedic” as a diagnosis — orthopaedic explained.
Matching quizzes are starting points, not proofs — how mattress matching quizzes work.
8. What does the trial actually allow?
Trial periods are not warranties. Note start date, soiling rules, collection fees and whether a break-in period is required first. Comfort dislike usually lives here, not in the warranty.
Also write how you are buying — showroom or distance — because legal refund rights change. A shop change of mind is not an automatic legal refund. A distance sale often has a 14-day cancel clock. A fault is a third track.
9. What does the warranty actually cover?
Read warranty explained: body impression thresholds, base requirements and what comfort dislike never covers. Keep the fire label on. See what voids a warranty.
10. Where does the old mattress go?
Book recycling or collection before the new one arrives. Same-day swap is not automatic. Fly-tipped mattresses are a local problem, not a product feature.
What should I write on one card before I pay?
| Write this | Why |
|---|---|
| Width × length in cm | Names fail across UK, EU, IKEA and US |
| Stacked height in cm | Fitted-sheet pocket depth |
| Approved base and slat gap | Wrong base is a usual warranty void |
| Support system and tension or density | Soft on the ticket may be the quilt |
| How you bought it | Shop visit vs online changes legal cancel rights |
| Trial start, fees, soiling rules | Comfort dislike lives here |
| Impression depth in mm | Warranty claims need that number |
| Fire label still on | Product identity and many claims |
The National Bed Federation says UK length and width are not a legal Act. Accepted industry practice is plus or minus 20 mm. That note was checked on 28 August 2026. A 149 cm King can still be a UK King. A 160 cm mattress is a different regional size. See UK vs EU sizes.
Should I buy in a showroom or online?
Either can work if you use this same list. In a shop, take questions to ask. Online, screenshot trial and warranty pages before you order. BedGuide does not take commission either way.
After you decide
How it works
Frequently asked questions
What should I check before buying a mattress in the UK?
Confirm UK size in centimetres, a suitable bed base and doorway access, then choose construction type and support for body weight. Check trial and warranty small print, and plan disposal of the old mattress before delivery day.
Is soft, medium or firm enough to decide?
No. Those words mix spring support and top feel and mean different things in different shops. Split tension or foam density from surface plushness before you compare models.
Should I buy online or in a showroom?
Either can work if you use the same checklist. Showrooms help you feel surfaces; online often has clearer trial rules. Ask the same construction questions either way — see questions to ask in a bed shop.
What is the difference between a trial and a warranty?
A trial is a period when you may return the mattress if you dislike it, under the seller’s rules. A warranty covers stated faults such as sag beyond a threshold. Comfort dislike is usually a trial issue, not a warranty issue.
What three numbers should I write before I pay?
Write mattress width and length in centimetres, the stacked height for sheets, and the approved slat gap for the warranty. Then write the trial start date and the body-impression depth. Soft, medium and firm are not those numbers.
Where do these facts come from?
BedGuide is desk research. The numbers and rules on this page were checked against the official or primary sources below. We name the check date. We do not invent a figure when a source is missing.
- National Bed Federation — regulations and standards — UK size names are industry practice. Accepted making spread is ±20 mm, which does not turn a UK King into a 160 cm EU King. Checked 2026-08-28.
- IKEA UK mattress size guide — Confirms some UK retail lines use extra centimetre sizes. Measure before you pair a frame, mattress and sheets. Checked 2026-08-28.