Which diaper size fits your little one?

Diaper sizes aren’t about age. They’re about weight and fit. Two four-month-old babies can easily wear different sizes. Below, you’ll find how to choose the right diaper size, how to tell when a diaper no longer fits and how to switch without the fuss.

Start with the weight on the pack

Diaper sizes are based on weight. Every pack shows the weight range each size is made for. Keep two things in mind:

Ranges differ between brands. Size 3 from one brand isn’t exactly the same as size 3 from another.
Sizes overlap. Your little one can fit the weight range of two sizes. At the top end of a size? The next size up is often a good bet.

Weight is a starting point. The fit tells you whether the size is really right.

How a well-fitting diaper looks

The waistband closes around the tummy without pinching. You can still slide a finger underneath.
The tabs fasten evenly on the front, without much stretching.
The ruffles along the legs point outwards and aren’t tucked in.
There are no gaps around the legs or at the back.
After taking the diaper off, you don’t see deep red marks.

Is the diaper too small?

These signs point to the next size up:

You have to stretch the tabs a lot, or they barely reach the front.
You see red marks around the waist or legs that don’t fade quickly.
The diaper leaks at the back or the top, especially with poos.
The diaper fills up faster than before, including at night.

Is the diaper too big?

A diaper that’s too big can leak too. Look out for:

space or gaps around the legs;
leaks along the legs;
a diaper that sags or twists;
tabs that overlap a lot.

Leaking even though the size is right?

Not every leak is about size. Check these points too:

Pull the ruffles along the legs outwards.
Make sure the diaper sits straight, at the same height at the front and back.
Changing a boy? Point his penis down before you close the diaper, so wee is less likely to escape at the top.
Change a little earlier when the diaper feels heavy, for example just before sleep.

Moving up a size, calmly

Babies can grow faster than you expect. So don’t stock up on one size when your little one is already at the top end of it. Try a smaller amount of the next size first.

At Lullabum, you can combine two sizes in the same box. That way you have both at home while your little one is in between. Is the new size a good fit? Change the size in your account. The change applies from your next editable delivery.

To work out how many diapers you need per box, read how many diapers a baby needs per day. Ready to choose? Build your box.

Red or irritated skin? If the skin stays red or irritated even when the size fits, ask your child health clinic (consultatiebureau) or GP for advice.