How to Choose the Right Diaper Size for Your Baby

Choosing the right diaper size isn't just about your baby's weight — fit and comfort matter just as much. Here's how to get it right every time.

Start with the weight range, but don't stop there

Every diaper pack lists a weight range (for example, Small fits 4–8kg, Medium fits 7–12kg). Use this as your starting point, but remember babies grow at different rates, and thigh and waist shape varies too.

Signs your current size is too small

• Red marks or indentation lines around the waist or thighs after removal
• Frequent leaks at the back or sides, even with regular changes
• You have to tug or stretch the diaper more than usual to fasten it
• Visible gaps have disappeared — the diaper looks stretched tight

Signs your current size is too big

• The diaper sags or droops, even when dry
• Frequent leaks around the legs because the fit isn't snug
• The waistband doesn't sit close to the skin

A simple size-check test

You should be able to fit two fingers comfortably under the waistband — snug, not tight, not loose. If it's tighter than that, size up. If there's extra room beyond two fingers, size down.

GoodDry pull-up pants sizes

GoodDry baby pull-up pants diapers are available in Newborn, Small, Medium, Large, Extra Large, and XXL, so you can size up as your baby grows without switching brands. Not sure which size to start with? Try our single-piece trial pack before committing to a full pack.