When it comes to finding the best diaper fit for your little one, size really does matter! Most leaks are caused by sizing issues, so getting the fit right is key to keeping tiny bottoms comfortable, dry and leak-free.
If you’re expecting your first baby, choosing a diaper size can feel a little overwhelming. And even if you’ve been through a few boxes already, your baby’s shape can change surprisingly quickly as they grow.
The most important thing to remember? Every baby is different, and every brand’s sizing is different too. Weight guides are a helpful starting point, but they don’t tell the whole story. Your baby’s body shape, movement and growth spurts can all affect which size works best.
So, rather than relying on the number on the pack alone, let the fit be your guide.
HANDY HINT! If you’re between sizes, it’s worth trying both to see which gives your baby the best combination of comfort and leak protection.
How do you know when to size up?
It might be time to move up a size if:
- The waistband sits low on your baby’s tummy or slips down easily
- The tabs barely fasten at the front
- The diaper leaves deep red marks or irritation around the waist or thighs
- You’re noticing more leaks, especially overnight or around the back
- Your baby seems uncomfortable or restricted
And if you’ve bought from us before, there’s one little thing to keep in mind: our new Blowout Blocker makes our diapers fit a little more snugly. So if you’re comparing a new pack with a previous size you’ve used, you may find the fit feels slightly different.
Or is it time to size down?
A diaper that’s too big can cause just as many problems as one that’s too small. Consider sizing down if:
- The diaper sags around the legs or bottom
- You can see gaps around the waist or legs
- The tabs overlap significantly when fastened
- Leaks happen because the diaper feels too loose
The perfect fit: what should you be looking for?
You’ve got the right size when the diaper feels snug but not tight. The waistband should sit comfortably just below your baby’s belly button, and you should be able to slide a finger comfortably inside it.
The tabs should fasten evenly and securely at the front, while the leg cuffs sit neatly in your baby’s leg creases. A quick tip that can make a big difference: after putting the diaper on, gently pull the ruffles and inner leg cuffs out so they aren’t tucked in.
The absorbent core should lie flat without bunching, your baby’s bottom should be fully covered, and the diaper should stay securely in place while still allowing plenty of freedom to wriggle, crawl and explore.
And remember, a good fit shouldn’t look or feel restrictive. Your little one should be able to move freely and comfortably, whether they’re having a sleepy night, a busy day of crawling or simply enjoying some tummy time.
What about diaper pants?
Once your little one starts toddling, walking and generally refusing to stay still during nappy changes, diaper pants can make life a whole lot easier!
Just like regular diapers, size matters. Diaper pants should fit snugly and comfortably while giving your little one the freedom to move, play and explore.
Look out for the same signs when choosing a size. If the pants leave deep red marks, feel tight around the waist or legs, sit low on the tummy, or you’re noticing more leaks or blowouts, it may be time to size up.
On the other hand, if they sag between the legs, slide down during movement or leave gaps around the waist or legs, a smaller size may give you a better fit.
The waistband should sit just below your baby’s belly button and lie smoothly against the skin without rolling or twisting. You should still be able to comfortably slide a finger inside, and the pants should stay securely in place without restricting movement.
Most importantly, your baby’s bottom should be fully covered and the absorbent core should sit flat without bunching.
A little trial and error is completely normal
Finding the right diaper size isn’t always a one-and-done decision. Babies grow in fits and starts, and what works beautifully one week might feel different the next.
And because sizing can vary from one brand to another, don’t assume that the same size will fit your baby in every diaper. When switching brands, use the individual brand’s weight guide as your starting point, then check how the diaper actually fits on your baby.
When in doubt, trust your baby. Snug, secure and comfortable is the goal — with no gaps, no digging and no unnecessary leaks.
Here’s to fewer leaks, fewer outfit changes and more time enjoying those lovely little moments!
