How to choose a baby diaper size

Start with your baby’s current weight, then check how the diaper sits around the waist, legs and side tabs. The weight range gives you a starting point. Your baby’s shape and movement help you understand the fit.

Sometimes you notice growth in the length of a sleeve, sometimes in the way your baby settles into your arms. Diaper sizing follows those small changes too. Reading the number on the pack alongside your baby’s everyday comfort makes the choice more personal.

How do diaper sizes relate to weight?

Begin with the weight guide for the brand you are choosing. KOZAMAN publishes the following size ranges on its product page:

Size 1: 2–5 kg
Size 2: 4–8 kg
Size 3: 6–10 kg
Size 4: 9–14 kg
Size 5: 11–16 kg
Size 6: 13–18 kg
Size 7: 15 kg and above

These ranges apply to KOZAMAN. You can see the current size guide and the diaper count for each pack on the baby diaper page. Start with your baby’s current weight and then look at how the diaper sits on their body.

What should you consider between two diaper sizes?

Some weight ranges overlap. A baby weighing 9 kg, for example, falls within both size 3 and size 4 in the KOZAMAN guide. Comfort around the waist and legs then helps guide the choice.

Centre the front and back of the diaper, fasten the tabs evenly and arrange the leg edges outward. Observe the fit as your baby moves. The aim is a diaper that follows their shape while leaving room for movement.

How can you check the fit?

At the waist: The front and back sit evenly, with the side tabs closing at similar levels.
Around the legs: The edges are arranged outward and follow the shape of the body.
During movement: Observe your baby’s comfort as they turn, play and settle into your arms.

Remembering these checks when you open a new pack can become a useful habit. It brings the weight guide together with everyday observation. We explore the role of softness and flexibility further in what makes a good baby diaper.

When should you consider the next size?

As your baby approaches the upper end of a weight range and the fit changes, consider the next size. The way the tabs fasten, the space around the waist and legs, and your baby’s movement all contribute to that decision.

Using current weight and fit, rather than a fixed age on the calendar, makes the choice specific to your baby. The same size may feel different at different stages of growth.

How does a size change affect your box plan?

The number of diapers in a pack can change with the size. KOZAMAN lists the pack count for every size separately. When choosing a new size, consider the total number in the box alongside your own daily use.

The calculation in our monthly diaper needs guide can help you plan this transition. Size, the diapers already at home and the delivery interval then become parts of the same routine.

A small choice, everyday comfort

Your baby’s weight is the starting point; their comfort is your most useful observation. Bring the two together when choosing a size. Explore KOZAMAN’s options and consider the box that fits your family’s routine.

Product reference: The weight ranges in this article reflect KOZAMAN’s published size and product information checked on 7 October 2026. Refer to the current product-page guide when making your selection.