How we size

1. You measure once, following the steps each tool shows, each with its source.

2. We apply each source's rule as it is written: a size chart row, a trade body's standard size or a maker's formula. We add no margin and no typical size. Where a tool combines sources (TV size: LG UK's rule sets the size; ITU's optimal viewing distance and, for Full HD, LG's own stricter rule can lower it) or a source is silent, the tool's How we worked it out section says the rule we use and why.

3. Every answer names its source, the date we checked it, the date of the next check and a confidence label.

A source is a maker's own size chart or spec sheet, a trade body such as the National Bed Federation, a standards body such as the International Telecommunication Union (ITU), or a charity such as Cycling UK.

We read a source only where the source's website allows it, both in its robots.txt file, where a website tells automated tools which pages they may read, and in its terms. We drop a source when either stops allowing it.

We download each page ourselves and keep the exact words we rely on. A figure we give as a source's own appears in those words. Any other number is either worked out from those figures by a rule the same page shows, such as a TV size for your seat, or is one of our own rules, which we say is ours.

Amazon listings are never a measurement source. A size here must come from whoever sets the rule, in their own published words, so we never use an Amazon page as a source.

• Exact

  The source gives one figure for this.

• Range

  Any size in a band meets the rule. No answer uses this label yet.

• Depends on the maker

  The answer rests on makers' own figures or rules, which can differ between makers.

• No recommendation

  Our sources do not support a size for this.

Exact: a trade body's UK bed size.

Range: no answer carries this label at the moment. A kids' bike answer can span wheel sizes, but each size comes from a different model's chart, so it is labelled Depends on the maker.

Depends on the maker: kids' bikes, where the answer comes from the makers' own charts and brands differ (Cycling UK says a child 'on some brands will fit a bike with wheels the next size up'), TV size, which follows LG UK's rule, and emperor and Euro bed sizes, which have no trade body figure.

Source: Cycling UK, the right size bike for a child (external site) checked 12 Oct 2026

No recommendation: when no source supports a size for your inputs. We say why, and show no products.

An answer is valid until its source's next check date, shown with the answer. A source past that date must be read again before we can next update the site, and the Sources page marks it Re-checking.

No. Commissions never change an answer or the order of products. Links marked Ad go to Amazon. We earn a commission on qualifying purchases made through them.

After an answer we may show models whose maker gives a size for them, in the size that matches your answer or, for TVs, the nearest screen size we have checked, with the maker's own figure and a link to the maker's own page. A No recommendation answer shows no products.

Models we checked are chosen from makers' own pages, never from Amazon data. Our product lists show products sold on Amazon UK, picked from Amazon UK's own category lists, with facts quoted from each listing. Our product lists explains them.

We picked these products from Amazon UK's own category lists, favouring products that were in stock and selling well there when we chose them. Each list follows Amazon UK's own sales ranking, read on the date shown above it; where a list combines several of Amazon UK's categories, it takes products from each in turn. Being listed, or listed first, is not a recommendation.

Products without a ranking follow the ranked ones, by the figure the list names above it, smallest first, then by name.

In our product lists, each name is taken from the product's Amazon listing and shortened by a fixed rule. The figures beside it are what the listing says, quoted from its title, its bullet points or its product details, with the date we read it. Columns marked (listing) hold them. We have not checked them with the maker, and they are not sources: the Sources page lists only the documents our answers rely on.

We hide each listing figure 45 days after we read the listing, and any answer worked from it goes with it.

Where a list has a UK bed size column, we put the size the listing gives beside the six UK bed sizes of the National Bed Federation. Figures must match in centimetres, exactly. On mattresses, toppers, mattress protectors and fitted sheets a size name alone is matched by name, and we also read the listing's bullet points: where its size name and its figures disagree, we say so, and where it gives two different sizes for the product, we give none. For bed frames, beds with mattresses and bed bases a size name alone gives no UK size: we use figures only where the listing says they are the mattress size, or where they are exactly the UK size it names.

Where a list has a seating distance column, it gives two seats from the same rules as our TV size tool: the seat LG's rule gives the listing's screen size for, and the closest seat the tool's limits allow for its resolution. Where LG's seat is closer than those limits, only the closest seat shows. We never give a furthest seat.

A kids' bike shows the inside leg from its maker's own chart only where the brand and model match a chart in our kids' bike size tool exactly. Every other list, duvets, pillows, curtains and rugs among them, shows the listing's figures only.