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How Bed Fit decides

Bed Fit works out what fits you from your answers and the rules on this page. Money from brands plays no part in that order. Here is every rule, how sure we are about it, and what we will do when shop links arrive.

Today: no partnerships, no shop links

bed.chat has no affiliate partnerships with any brand or shop, and no page or answer links to a product to earn money. If that changes, this page will say so first, with the date.

Two steps, always in this order

  1. Fit first. Your answers and the rules below decide the mattress type, the firmness range and the size. Bed Fit also says what it rules out and why.
  2. Links after. Only once the answer is fixed would any shop link be added, and whether a shop pays us cannot move anything up or down. Before any link goes live, we check that swapping or deleting every commission in our product list leaves the order unchanged.

The rules, with their evidence

Drawn from sleep, back-pain and allergy research we read in October 2026. The evidence level travels with every reason Bed Fit gives you.

  1. Rule 1. Long-standing lower back pain

    Lean medium-firm. Not the firmest you can find.

    Randomised trial of 313 adults with chronic low back pain (Kovacs, Lancet 2003); systematic reviews by Radwan (2015) and Caggiari (2021).

    Moderate

  2. Rule 2. Anyone told "firmer is better for your back"

    The firmest mattresses did not beat medium-firm in the trials. In Kovacs 2003 the firm group did worse.

    Same trial and reviews as rule 1.

    Moderate

  3. Rule 3. Body weight

    Heavier bodies tend to need firmer support, lighter bodies softer. Medium was the most consistent across body types.

    Small spinal-alignment studies across weight and BMI groups (BMJ Open Respiratory Research abstract; Monash study of 150 adults).

    Weak to moderate

  4. Rule 4. Sleep position

    Side sleepers need shoulders and hips to sink in enough. Back sleepers need the lower back held up.

    Pressure-mapping and alignment studies (Hui 2017; Vitale 2023 MRI study, 20 people).

    Weak to moderate

  5. Rule 5. Sleeping hot

    Breathable or heat-conducting builds can feel cooler, but a 2025 review of trials found no clear effect on sleep itself.

    Herberger 2019 and 2024 trials; Pasquier 2025 systematic review and meta-analysis of 9 trials.

    Weak

  6. Rule 6. Sharing with a light sleeper

    Pick a build that passes on little movement (memory foam, pocket springs), a bigger bed, or two singles.

    Rayward 2025 systematic review; lab study of mattress motion transfer and sleep stages.

    Moderate

  7. Rule 7. Dust-mite allergy

    Allergen-proof mattress covers help children with dust-mite asthma. For adults, covers on their own helped little.

    Murray 2017; Halken 2003 (children); Woodcock 2003, NEJM (adults).

    Strong strong for children, weak for adults

  8. Rule 8. Older, or getting up is hard

    Avoid very soft mattresses and very low beds. The top of the mattress at least at knee height; a grab handle helps.

    Small care-setting studies (Mount 2006; Knobel 1996; Erdkamp 2024).

    Weak to moderate

  9. Rule 9. Is it time to replace?

    Sagging, waking stiff, or sleeping better elsewhere are the signs. "7 to 10 years" is a trade rule of thumb, not a tested limit.

    Jacobson 2010 (people on ~9.5-year-old mattresses improved on new ones); year ranges from industry bodies.

    Moderate the year range is industry practice

  10. Rule 10. Judging a new mattress

    Give it about 30 nights before you decide, so a usable trial and clear returns are part of the choice.

    Bader 2000 on adapting to a new sleep surface; brands also suggest 30 to 45 days.

    Moderate

  11. Rule 11. Pillows (coming later)

    No single right height: the aim is a neck that stays level for your position.

    Lei 2021 systematic review; Ren 2016.

    Weak to moderate

Medical-sounding labels are marketing. A 2021 systematic review (Caggiari) found too little evidence behind mattresses sold as therapeutic. Bed Fit does not repeat those claims, and if pain keeps you up or lasts, it will suggest a doctor or physiotherapist.

What the evidence levels mean

LevelMeaning
Strong Several controlled trials point the same way.
Moderate At least one good trial or consistent reviews, with limits.
Weak to moderate Small lab studies that agree in direction, little long-term data.
Weak Small or conflicting studies; treat as a reasonable guess.
Industry practice What makers and retailers say. Not tested independently.

Which sources count, and for what

Sources are sorted into five tiers. Tiers 4 and 5 can never decide a recommendation on their own.

  1. Tier 1

    Research, regulators, standards bodies

    Used for: Decides rules.

    Trials and systematic reviews; consumer regulators such as the UK CMA and ASA; standards such as US 16 CFR 1513.

  2. Tier 2

    Independent testers that buy their own samples

    Used for: Decides firmness and durability where they have tested.

    Which? (UK), CHOICE (Australia), Consumer Reports (US).

  3. Tier 3

    Owners talking to each other

    Used for: Experience, not test results.

    Patterns that come up again and again in owner forums.

  4. Tier 4

    Review sites paid by commission

    Used for: Quoted as "a review site says", always labelled.

    Most "best mattress" lists; many are sent free samples.

  5. Tier 5

    Brands

    Used for: Only for specs and the wording of their own terms.

    Dimensions, trial and warranty text.

Firmness is where this matters most. Brands label their own firmness, and an Australian independent test found mattresses sold as "firm" that measured close to soft. Where an independent tester has data, we use it; otherwise we say the firmness is the brand's own label.

When we add shop links, these rules apply to every one:

  • The ranking is worked out first, without commission data; links are attached afterwards.
  • Each link is labelled right next to it, saying whether we earn from it. Not only in the footer.
  • Every recommendation includes an option we earn nothing from, or says plainly that there isn't one at that price.
  • Bed Fit says why it left out the types and well-known brands it did not choose.
  • No crossed-out "was" prices, no ticking timers and no "ends soon" pressure. We show the price you would pay and the date we checked it.
  • Prices, trial lengths and return terms carry the date we checked them, and are rechecked within six months.
  • We do not bid on brand names in search ads.

Why we are strict about this

Mattress reviews have a history. In 2016 one mattress brand sued several review sites, saying they had not clearly disclosed money from competitors. Large review sites say in their own disclosures that they earn commission and that most of the mattresses they test are sent free by the makers; a few testers, such as Which?, CHOICE and Consumer Reports, buy their own. In the UK, the advertising regulator ruled in 2025 that one brand's crossed-out prices misled buyers, and in 2026 the competition authority made another stop using misleading urgency claims.

Brand quizzes recommend their own mattresses. Bed Fit's job is to tell you what fits, including when the answer is a cheaper or plainer mattress.

Last reviewed 28 October 2026.