Baby Clothes Sizes: How to Pick a Gift That Fits

The number on the label isn't an age or a weight, it's the maximum body length the garment is made for. Size 62 therefore fits a baby measuring up to about 62 cm, and covers everything from roughly 57 cm. It comes from the European standard EN 13402, under which children's clothing is sized by body height.

The age that shops print next to the size (say "2–4 months") is just a conversion based on an average baby. According to the WHO growth standards, the average boy measures about 61 cm at three months and around 76 cm at one year, with girls a centimetre or two shorter. Any individual baby can easily be a whole size off the average, in either direction.

Two more practical points: a double label such as 62/68 means the piece will last across both sizes (it tends to be roomier or has a turn-up cuff), and cotton shrinks a little after its first hot wash. Cuts also vary from brand to brand – with some makers, a 68 comes up rather narrow and short.

The adorable little romper in size 50 is the gift most likely to end up in a box with the tag still on. There are four reasons.

Babies are born right at the limit. The average newborn is around 50 cm long, so half of all babies are already bigger than size 50 on day one. And babies grow fastest in the first weeks – according to the WHO curves, they gain about 4 cm a month over the first two months.

Everyone gives it. A new-baby gift tempts people towards the smallest size because it looks the cutest. Parents end up with ten outfits in size 50 and only a few weeks to wear them.

The first weeks are all about comfort. A newborn gets changed several times a day, so at home it's bodysuits, sleepsuits and zip-up all-in-ones that win. Little dresses with buttons down the back or a smart shirt practically never get a turn in the first six weeks.

The season is wrong. A thick size-56 snowsuit for a baby born in April won't get used before winter, because by November the baby will be three sizes bigger.

Size 44 is designed for premature babies, who are born smaller and lighter. You won't usually find it in ordinary shops, and it doesn't belong in the layette for a full-term baby – even a small newborn will probably fit it for only a few days.

If the baby arrived early, though, it's exactly the gift parents don't have: they weren't expecting the baby so soon, and a standard size 50 is too big. Do ask first what they need – hospitals often have rules about what premature babies can wear, and front fastenings and soft seams matter more than looks.

A rough starter wardrobe for a full-term baby for the first three months. The quantities are a sensible baseline, not a rule – it depends how often you do the washing.

Clothes are the gift most likely to miss, because you're aiming at a number that changes every month. If in doubt, stick to the rule of "two sizes bigger than the baby is now", or pick a gift that doesn't depend on size at all. For ideas on sharing out new-baby gifts with others, see New-baby gifts: three piles and what goes where, and for christenings, Christening gifts: who gives what and how to avoid doubling up.

If you'd like to give something the baby won't outgrow in a month, it could also be a personalised book in which the child, based on a photo, is the hero. For a newborn it's more of a gift for later – it makes sense once they can listen to a story, for example for a first birthday.