Most cot shopping starts with looks — the wood tone, the shape of the sleigh ends — but the specs that actually affect safety and day-to-day use are slat spacing, base height and mattress fit, all of which are easy to check and easy to overlook next to a nice finish.

Step 1. The UK Standard Cot Mattress Size Is 140 x 70cm

Most full-size cot beds sold in the UK are built around a 140 x 70cm mattress, which is why bedding, fitted sheets and mattress protectors are almost universally sold to that measurement. A cot built to a non-standard size — some imported or older designs — means hunting for compatible bedding indefinitely rather than picking from the widely available standard range.

Checking a specific cot's actual mattress dimensions before buying, not just assuming "cot-size fits all," saves exactly this hassle later — the Mamas & Papas Harwell Cotbed, for example, states its required mattress size directly (L140 x W70 x D10cm) rather than leaving it to guesswork.

Step 2. Slat Spacing Is a Genuine, Checkable Safety Spec

UK and EU safety standards require cot slats to be no more than roughly 6-7.5cm apart, specifically so a baby's head or limbs can't become trapped between them. Every cot legally sold new in the UK meets this as standard — it's not something you need to measure on a new purchase, but it's exactly what you're checking for if buying secondhand, vintage, or an imported piece from outside the UK/EU market.

This is the one spec where "looks fine" isn't good enough to rely on — a few millimetres either side of the safe range isn't visible at a glance, which is why it's a certified standard rather than a judgement call.

Step 3. Adjustable Base Height Exists for a Specific Reason, Not Just Convenience

Most cot beds offer two or three base heights — the Mamas & Papas Barton Cotbed, for instance, has three. Starting at the highest position means less bending to lift a newborn in and out; lowering it as the baby starts to sit and pull up keeps them safely below the rail height once they're mobile.

This isn't a nice-to-have feature so much as a sequence you're meant to actually use as your baby grows — check that a specific model's height adjustment is easy to do without fully dismantling the cot, since it's something you'll be changing more than once.

Step 4. Wood Type Affects Durability More Than Safety — the Finish Is What's Regulated

Solid wood (oak, pine) is heavier and generally more durable than MDF or veneer construction, but the actual safety-relevant spec is the paint or finish, which has to be non-toxic and lead-free on anything legally sold in the UK. This makes wood type mostly a durability and aesthetic choice between compliant products, not a safety differentiator — the real caution is around older, secondhand, or non-UK-market furniture where finish standards may not have applied.

A solid wood cot bed, like the Obaby Stamford Classic or Snuz SnuzKot Skandi, will generally handle years of use and a toddler-bed conversion better than a lighter MDF frame — worth factoring in if you're planning to keep the piece through the cot-bed conversion stage.

Step 5. Teething Rails Protect Both the Baby and the Wood

Some cot beds, including the Babylo Harmony, include a plastic or silicone strip along the top rail specifically because babies chew on it once they start pulling up to stand — a genuine, common stage, not a rare edge case. This protects a baby's gums from splinters or rough edges and protects the cot's finish from tooth marks at the same time.

Worth checking for on any cot you're expecting a toddler to actually stand and chew on, which is most of them once they're mobile — it's a small detail that saves the finish from real wear.

Step 6. "Cot Bed" Means It Converts — That's a Real Functional Difference, Not Just Marketing

A basic cot is fixed-size and used only for infant sleep; a cot bed, like the CuddleCo Clara or Obaby Nika, converts into a toddler bed by removing one side rail, extending its useful life by several years for a moderate price premium over a basic cot.

This conversion is worth checking is actually included (some ranges sell the toddler-bed conversion kit separately) rather than assumed — "cot bed" in the name is a genuine functional promise, but confirming what's included with the base price avoids a surprise add-on cost later.

Quick Picks by Budget

Budget: Obaby Nika Cot Bed — £250, solid wood, converts to a toddler bed.

Mid-range: CuddleCo Clara Cot Bed — £399, solid wood.

Premium: Oxford Cotbed & Mattress Bundle — £715, includes the mattress.

FAQ

What's the standard UK cot mattress size?
140 x 70cm is the standard for most full-size cot beds, which is also the size most UK-sold bedding and mattress protectors are made to fit. See Step 1.

How far apart can cot slats legally be?
No more than roughly 6-7.5cm, a UK/EU safety standard that every legally sold new cot meets. Worth checking specifically on secondhand or non-UK-market furniture. See Step 2.

Is a cot bed worth the extra cost over a basic cot?
Usually yes, if you want the furniture to last past infancy — a cot bed converts to a toddler bed and gets several more years of use for a moderate premium. Check the conversion kit is included, not sold separately. See Step 6.

Does the base height actually matter?
Yes — starting high (easier lifting for a newborn) and lowering as the baby becomes mobile is a genuine safety and practicality sequence, not just an extra feature. See Step 3.