A diaper (a nappy in the UK) holds in pee and poop. Whatever covers your baby's bottom goes over it: a bodysuit (US parents say onesie), pants, a dress or a sleepsuit. So each of those needs room for the diaper.
- For ages0–3years
- You'll need10–12a day
- Wear itAll year
Can a baby wear just a diaper?
Yes, in a hot room. From 28°C (82°F) indoors, a diaper alone is enough. Below that, start with a short-sleeve bodysuit and add layers as the room cools.
To check, feel your baby's chest or the back of the neck (the neck check). Warm and dry is right, and cool hands and feet are normal. If it is hot or sweaty, move to the coolest room and point a fan away from your baby. If it is cool, add a layer.
Outside, a diaper alone leaves most of the skin bare to the sun, so use shade and light clothes. The hot weather guide and the sunny weather guide explain how.
Types of diaper
Most families use disposable diapers, which are used once and thrown away. They are slim under clothes, and the waterproof layer is built in.
Tape diaper
The usual diaper from birth, made in every size. The half with the tabs goes under your baby's bottom, the front comes up between the legs, and the tabs close it at the front, so you can set the fit at every change.
Diaper pants
Pulled on like underwear and torn open at the sides to take off, so you can change a baby who rolls away or stands. They hold as much as a tape diaper. Most start at size 3 or 4, and babies often switch at about 6 to 9 months.
Swim diaper
Made for the water. A regular diaper gets heavy in a pool and can split open.
Cloth diapers
Washed and used again. A cloth diaper is thicker at the hips and bottom than a disposable, so clothes need more room. Many come in one size that adjusts with snaps, from about 3.6 to 16 kg (8 to 35 lb), and some come in a newborn size that fits a small baby better.
Prefold
A rectangle of cotton that you fold and lay inside a waterproof cover. The cheapest way to use cloth, and the hardest to learn, because of the folding.
- Good: Costs the least
- Not good: Folding takes practice
- Not good: Needs a waterproof cover
Fitted
Shaped like a diaper, with elastic legs and snaps, and absorbent all over. It needs a waterproof cover on top. It holds a lot, so it works well at night, but it is bulky.
- Good: Holds a lot, good for nights
- Not good: Bulky under clothes
- Not good: Needs a waterproof cover
Pocket
A waterproof outer with a pocket inside. You push an absorbent pad (an insert) into the pocket, and add a second one when you need more. No folding and no separate cover, but the whole diaper goes in the wash each time, so you need more of them.
- Good: No folding, cover built in
- Good: Add an insert for more
- Not good: All of it washed each time
All-in-one
The waterproof outer and the absorbent layer are sewn together, so it goes on like a disposable. The easiest kind to start with, and the most expensive.
- Good: Goes on like a disposable
- Good: One piece, nothing to fold
- Not good: Costs the most
What is a diaper cover?
Shops use the name for two different things.
Waterproof cover
A waterproof wrap for a cloth diaper that has no waterproof layer of its own.
Bloomers
Short, plain cotton pants with elastic legs, also sold as diaper covers. They go over a diaper, under a dress. They are not waterproof, so they never replace a waterproof cover.
Diaper sizes
Diapers are sized by weight, not age. Each pack prints the weight its size fits. The ranges overlap, and each brand sets its own, so the same size number can fit differently from one brand to the next.
Sizes run from preemie and newborn up to size 7 or 8. The newborn size usually fits up to 4.5 kg (10 lb), and many babies outgrow it within the first month. A big baby may skip it and start in size 1, which begins at about 3.6 kg (8 lb).
As a rough guide by age: size 1 to about 3 months, size 2 to about 6 months, size 3 to about a year, size 4 to about 18 months, then size 5 and up into the toddler years. Two babies of the same age can be two sizes apart, so go by the weight on the pack and the fit.
The diaper size chart guide goes further: newborn or size 1, when to size up, and the questions parents ask.
Find the size by weight
4.0 kg (8.8 lb)
Sizes that fit
NewbornUp to 4.5 kg (10 lb)- orSize 13.6–6.4 kg (8–14 lb)
PreemieUp to 2.7 kg (6 lb)
NewbornUp to 4.5 kg (10 lb)
Size 13.6–6.4 kg (8–14 lb)
Size 25.4–8.2 kg (12–18 lb)
Size 37.3–12.7 kg (16–28 lb)
Size 410–16.8 kg (22–37 lb)
Size 512.2+ kg (27+ lb)
Size 615.9+ kg (35+ lb)
Size 718.6+ kg (41+ lb)
Typical weights printed on the packs. Size numbers mean different weights in the US and in the UK and Europe, so read the weight on your pack.
How to tell it fits
1. Snug at the waist
The waistband sits just below the navel, and two fingers slide under it. The two tabs land evenly on the front, without overlapping.
- Good: Two fingers fit under the band
- Good: Tabs even on both sides
- Not good: Tabs overlap or barely reach
2. Leg cuffs pulled out
After you fasten it, run a finger around each leg so the soft frilled edges stand out. A cuff tucked inside is a common cause of leaks.
- Good: Frilled edges stand out all round
- Good: Snug at the thighs, no gaps
- Not good: Edge tucked in at the leg
3. The whole bottom covered
Check the back too: the diaper should cover the whole bottom. Blowouts (poop escaping up the back) usually start there, because the back is the hardest place to seal.
- Good: Looks straight and even all round
- Not good: Bottom peeks out at the back
- Not good: Twisted to one side
Before you buy a big pack
Babies come in different shapes, and so do diapers, so one that never leaks on one baby can leak every day on another. Buy one small pack each of two or three brands first. Keep the one that fits with no leaks and no red marks, then buy that one in bigger packs.
When your baby moves up, start the new size with a small pack again, and stock up once you know it fits.
Cloth works the same way. Start with a trial set of 6 to 8 diapers of a few kinds, use them for a few days, then buy a full set of the kind you like.
Questions parents ask
Can my baby sleep in just a diaper?
Yes, newborns too, once the room is 28°C (82°F) or warmer, with no sleep bag (sleep sack) or swaddle on top. A diaper alone is fine in really hot weather, and better than overheating, which can raise the risk of sudden infant death syndrome (SIDS). Below 28°C (82°F), follow the sleep guide.
When should I move up a diaper size?
When the diaper leaves red marks on the tummy or thighs, the tabs only just reach the middle, or it no longer covers the whole bottom. Leaks that keep coming when it is on well often mean it is too small as well. In the first months, check the fit every couple of weeks.
Why does my baby's diaper keep leaking?
Usually the fit. Go through the three checks above, and with a boy, point the penis down before you fasten, which helps stop leaks. If it still leaks, look at the legs: gaps there mean the diaper is too big, and the answer above lists the signs of too small. If the size is right, try another brand.
How many newborn diapers do I need?
A newborn needs changing about 10 to 12 times a day, so about 70 to 85 diapers a week. Because many babies outgrow the newborn size within weeks, and big babies skip it, buy only a pack or two of it and have size 1 ready.
Should I size up diapers at night?
It can help. A bigger diaper holds more for the long night, as long as it still fits snugly at the legs. An overnight diaper, which holds more in the same size, is the other fix. With cloth, add an extra pad (a booster), or use a fitted diaper.
Do you need a diaper cover?
Not with a disposable, a pocket or an all-in-one diaper, because the waterproof layer is built in. A prefold or fitted cloth diaper needs one. Bloomers are optional: they keep a diaper out of sight under a dress.
Do cloth diapers fit under clothes?
Yes, most clothes fit. Check the bodysuit: snaps pulled tight between the legs squeeze a cloth diaper and can make it leak, so choose the next bodysuit size.
Which pants fit over a cloth diaper?
Pants with a stretchy waist and a roomy bottom, such as joggers or harem pants. A size up with the cuffs rolled works too. Skinny jeans leave no room, so skip them.
Are diaper pants the same as training pants?
No. Diaper pants are full diapers in a pull-on shape. Training pants are made for potty training: they hold less and feel more like underwear, which helps a toddler notice when they need the potty.
Should a newborn's diaper cover the cord stump?
No. The stump is the bit of umbilical cord left on a newborn's tummy. Keep the diaper folded below it, so urine doesn't soak it. The stump should fall off by 3 weeks of age, and then the fold is no longer needed.
