Nappy buying guide: which size to buy and what to look for

How do you know that a nappy’s the right fit? How can you tell when it needs changing? Is it OK to leave your newborn in the same nappy all night? We have the answers to all these nappy knowledge questions – and more…

dad changing newborn's nappy

Nappies are nappies are nappies, right? Just pick a pack, bung them your baby, and off you go. Well, not really. For the best, most-leak-free, most-kind-to-baby-bottoms nappy experience, you need to get the fit, the features, the sizing and the changing rules right.

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“There’s a huge range of disposable nappies to choose from today and you want to be sure you are making the best choice for your little ones,” says registered midwife Lesley Gilchrist, who’s featured Channel 4’s One Born Every Minute and is co-founder of My Expert Midwife.

Here, we answer the key questions parents – and parents-to-be – ask when they’re genning up on nappy know how…

newborn baby nappy change

What are the quality features to look for when choosing a nappy?

At MadeforMums, we test 100s of nappies each year – using both parent testers and our in-house MFM Lab Team.

Our Lab Team testers focus on how well nappies cope with absorbing liquid and how evenly that liquid is spread throughout the nappy, while our parent testers report back on comfort, ease of use and ‘leakability’.

And while many nappies score very well on every point, what marks the top nappies out from the rest is often the clever extra features that make nappy-changing easier, smoother and altogether less hassle. These key extra features, all of which you can find in the award-winning Lidl Lupilu range of nappies, include:

  • Good, adjustable tabs: High-quality tabs are really important. “Nappies that have tabs on which can be altered and resealed are good,” says Lesley, “so, if you check a nappy but don’t need to change it, you can do it up again nice and easily.” Also nappies with a generous tab ‘sticking area’ mean you can easily adjust the fit of the nappy as your baby gets a little bigger.
  • Soft material around an absorbent core: Hard to assess, we know, without actually opening a packet but great nappies feel super-soft and have an excellently absorbent core that keeps moisture away from your baby’s skin.
  • A wetness indicator: This newborn-nappy feature is a line that changes colour when the nappy’s wet, so you’ll know it’s time for a change without undoing the nappy. “A wetness indicator can be particularly helpful when you’ve got a newborn,” says Lesley, “as newborns wee a lot but, due to most nappies’ high absorbency, it can be difficult to tell otherwise.”
  • Navel recess: For newborns, a nappy with a gentle navel recess scores points for fitting gently around (rather than over) your baby’s umbilical stump.

How do nappy sizes work?

Nappy sizes range from newborn all the way through to potty training pants for toddlers.

“If you look on nappy packaging, you’ll see that nappy sizes are calculated by your baby’s weight – in kgs or lbs – instead of their age,”says Lesley.

The weight bands for each size can vary from nappy brand to nappy brand but not hugely. Here’s a size chart for Lidl’s Lupilu nappies, to give you an idea of what you might see:

Lidl's nappy size chart
Pic: Lidl.co.uk

Obviously, no 2 babies will weigh the same, so it’s impossible to tell you what weight your baby will be at what age (you can find out for sure at your local baby clinic or by weighing yourself first, then weighing yourself with your baby in your arms and working out the difference). But you can use the table below, as a general rule of thumb:

  • 0 to 1 month: 2kg to 5kg
  • 2 months: 5kg to 6kg
  • 3 months: 6kg to 7kg
  • 4 months: 7kg
  • 6 months: 8 kg
  • 9 months: 9kg
  • 12 months: 10kg

What does the + sign mean on some nappy sizes?

It’s not about size – although, looking at the weight charts on packaging, you’d be forgiven for thinking it might be as, for example, a Size 4+ nappy is indeed just a little bit bigger than a Size 4 nappy (but not as big as a Size 5).

But the real reason a nappy has a + sign on it is to show that it’s a nappy with increased absorbency. These come into their own when your child is sleeping through the night and you need a nappy that will make it through the wee hours (in both senses!) without leaks.

Which size nappy is best for newborns?

This totally depends on how much your baby weighs when they are born. But the vast majority of new parents find themselves using a Size 1 nappy for their newborn – with a smaller number of parents whose baby’s birthweight was more than 5kg starting off with a Size 2 nappy.

Which size nappy is best for a 6-month-old?

If there were 5 6-month-olds at a baby group, it’s very unlikely they’d all be wearing different nappy size! Generally speaking, a 6-month-old would be in a Size 3 or Size 4 nappy but remember that it’s weight, not age that is the indicator of which nappy size your baby needs to wear.

“Rather than thinking about age,”says Lesley,”focus instead on the nappy-size weight range you baby best fits into.”

Of course, if you are worried about your baby’s weight in any way at all, you should speak to your health visitor or GP.

How do I make sure my baby’s nappy fits properly?

“A nappy should be a snug fit for your baby without being restrictive,” says Lesley.

“Snug means you should be able to slide 1 or 2 fingers into the top of the nappy’s waistband once it is fastened. If you can’t – or if red marks appear around your baby’s tummy – it’s likely that the nappy is too tight and the tabs need loosening for your baby’s comfort and to stop skin chafing.

“If the tabs are difficult to fasten or too stretched, it may be that you need to move up a size for a better fit.”

As well as ensuring the waist is snug, make sure leg cuffs wrap neatly around your baby’s legs and bottom, says Lesley. “Don’t tuck the cuffs in – this is often a cause of leaks. Release the cuffs by running a finger around each leg.”

small baby having nappy change

How do I know when to change to a new nappy size?

“Even without checking your baby’s weight, it should also be fairly obvious when you need to change to a larger nappy size,” says Lesley, “as your baby will look visibly more restricted and the tabs to close the nappy will become tighter.

“Also, the nappy may no longer seem to be fitting well in other ways – it could be rubbing, for instance, around the top of the legs and tummy, causing soreness and redness. You might also be experiencing more leaks.”

It’s worth noting that when you first go up a size, the new nappy will probably look vast. “The next size of nappy will seem much bigger to begin with,” says Lesley, “but you will soon get used to it and the tabs can always be adjusted to provide a closer fit.”

And if you’ve taken the leap a little too soon, you’ll soon know about it: key signs are a low-hanging nappy, even when dry, and (sorry!) the odd leak.

How do I know when to change a nappy?

If your baby has done a poo, the smell will be a good indicator – and your baby may well also let you know by crying (lots of babies really don’t like sitting in a soiled nappy).

If it’s just a wet nappy, you may not realise straightaway – although, again, some babies do let you know by crying that their nappy is wet. If the brand of nappy you buy has a wetness indicator, that can take the guesswork out of the situation – and you will find that you soon get a ‘feel’ for when the changing mat calls.

“Wet nappies feel heavier,” says Lesley, “and, in time, you’ll recognise that heavier feel and will quickly be able to tell that it’s time for a change.”

dad changing baby at changing station

How many nappies should I expect to get through in a day?

We’re afraid there is no magic answer to this one as it does really depend on your baby and their bowels!

“As a guide, though,” says Lesley, “you can expect that a newborn baby’s nappy will need changing around 8 times a day – plus or minus a few, depending on how many times they have a poo.”

As they get older, they may go through fewer nappies than this or the nappy churn may remain at the same level – so it’s really just a case of responding to your baby’s needs.

“To protect your baby’s bottom from any redness or soreness, try using a gentle barrier cream (find out that’s suitable from birth) at each nappy change,” says Lesley.

How long is it OK to leave a baby in a wet nappy?

“You really don’t need to change a baby’s nappy milliseconds after every wee: today’s nappies are designed to be highly absorbent,” says Lesley.

Not only that but the materials used inside good nappies work to keep the urine from your baby’s skin, so it’s OK not to leap to the changing mat straightaway.

“But equally a baby shouldn’t be left for ages in a heavily soaked nappy,” says Lesley. “The more contact your baby’s skin has with wee, the more likely they are to develop some skin irritation, which could, eventually, lead to nappy rash.”

So, essentially, use your common sense: there’s no need to panic if you’ve popped to the shops and your baby’s done a wee in their nappy; you can change the nappy when you’re home. But if you’re going to be out for hours, it might be wise to find a suitable changing spot before too long.

Do I need to change my baby’s nappy if they have done a poo and then fallen asleep?

Every parent knows how gutting it is to do something that’ll wake a sleeping baby – especially if you’ve just spent hours rocking and coaxing it to sleep.

Like with lots of things in parenting, the answer here depends on the situation.

“If your baby is having a short nap, it’s probably OK to wait until they wake up before changing them,” says Lesley.

“But if it’s a longer sleep or overnight or if your baby already has damaged red skin or nappy rash, it would be advisable to change them nice and quickly to prevent any further irritation.”

night time nappy change

Can a baby go all night without a nappy change?

Obviously, ‘all night’ means very different things to different parents: for some (very lucky) ones, it’s a regular 7pm to 7am, for some it’s a few hours of darkness at a stretch – and for others it’s a not-even-close-to-getting-there-yet future parenthood goal.

“But, if your baby sleeps for a long period at night, it’s probably fine not to do a nappy change – as long as they go down to sleep in a clean dry nappy and they don’t already have some skin irratation or nappy rash,” says Lesley.

“Many nappies are absorbent enough to hold large quantities of urine and contain materials that will keep the moisture away from your baby’s skin.”

How does a disposable nappy work?

Disposables are single-use nappies. Underneath the soft inner layer that sits against your baby’s skin is the main core of the nappy where the wee is soaked up.

The core usually contains wood pulp or cellulose (look for FSC-certified cellulose as a sign of a more sustainably sourced manufacturing process) and a substance called sodium polyacrylate that turns to a super-absorbent gel when it gets wet, drawing away the moisture from your baby’s bottom.

Sodium polyacrylate is non-toxic. Occasionally, it can leak through the lining of a very wet nappy and you’ll see tiny crystals on your baby’s skin, which you can simply wipe off.

What about my newborn’s umbilical stump? How do I fit the nappy around that?

If you don’t have a nappy with ‘navel recess’ that’s designed to fit around your baby’s umbilical stump, you can fit your baby’s nappy over their umbilical cord stump or fold it down, so that the stump is exposed.

“Either way is fine,” says Lesley. “What is more important is that the stump is kept dry, so it heals and doesn’t become an environment where bacteria can thrive.”

To help with this, try to dress your baby in loose, unrestrictive clothing and make a little time each day to expose their cord stump to circulating air. You could do this by leaving their nappy off for short while and placing your baby on a towel or an absorbent mat – in case of accidents.

About our author Rachel Mostyn

Rachel has been writing about parenting since the birth of her 1st child in 2007 – for titles including The Guardian, The Telegraph, The Daily Mail, The Sun, Red, Marie Claire and Woman. She lives with her husband and 3 children in Bristol and estimates that she has used well over 10,000 nappies in their lifetime! She recently came back from a family sabbatical to South America and has just qualified as a foster carer. She is also co-founder of a social enterprise, The Women’s Work Lab, supporting mums from challenging backgrounds back into work.

RachelMostynheadshot

Pics: Getty Images

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