Sizing
Baby clothes size chart by age, height and weight
Which size to buy for a baby from 0 to 24 months: a size chart with height, weight, chest and waist, how to measure a baby, and when to size up.
How baby sizes work
Baby clothes are labelled by age in months: 0–3M, 3–6M, 6–12M, 12–18M and 18–24M. Babies grow at very different rates, though, so the age on the label is only a starting point. Your baby’s length (their height, measured lying down) is the most reliable guide, then their weight.
Our sizes follow standard international baby sizing. The chart below shows the body measurements each size is made for, not the measurements of the garment itself.
Baby size chart
Body measurements in centimetres and kilograms, with inches in brackets. Between sizes, choose the larger one.
| Size | Height cm | Weight kg | Chest cm (in) | Waist cm (in) |
|---|---|---|---|---|
| 0–3M | 56–62 | 4–6 | 40–42 (15.5–16.5") | 40–42 (15.5–16.5") |
| 3–6M | 62–68 | 6–8 | 42–44 (16.5–17.5") | 42–44 (16.5–17.5") |
| 6–12M | 68–80 | 8–10 | 44–47 (17.5–18.5") | 44–46 (17.5–18") |
| 12–18M | 80–86 | 10–12 | 47–49 (18.5–19.5") | 46–48 (18–19") |
| 18–24M | 86–92 | 12–13.5 | 49–51 (19.5–20") | 48–50 (19–19.5") |
Measurements of your child’s body, not of the garment. They follow standard international children’s sizing.
How to measure a baby
- Length: lay your baby on their back on a firm, flat surface, gently straighten their legs, and measure from the top of the head to the heel. It is easier with two people.
- Weight: use the latest weight from your baby’s check-up or vaccination card.
- Chest: measure around the fullest part of the chest, under the arms, with the tape comfortably loose.
Signs it is time for the next size
- The snaps between the legs strain, or the suit pulls at the shoulders when your baby stretches.
- In a footed sleepsuit, their toes reach the end of the feet. Covered feet should leave room for the toes to move.
- Sleeves or legs finish well above the wrist or ankle.
- The neckline is a struggle to get over their head.
Buying ahead, or buying a gift
Babies outgrow the smallest sizes quickly, so for a newborn gift 3–6M is often the more useful choice, and it will fit for longer. For seasonal pieces, such as a winter jumpsuit, think about the size the baby will be when the weather turns, not the size they are today.
Quick answers
What size should I buy for a newborn?
Most newborns wear 0–3M, which is made for babies up to about 62 cm long and 6 kg. It will be a little roomy at first and then fit for the first weeks to months. A larger baby may be ready for 3–6M sooner.
Is 0–3 months the same as newborn size?
Not quite. Some brands also make a smaller “newborn” size for babies under about 56 cm. Our smallest size is 0–3M, which fits from about 56 cm.
Should I buy baby clothes a size bigger?
If your baby is near the top of a size, or you are buying for a few months ahead, yes. Babies grow fast in the first year, so the larger size gets more wear.
What age is 12–18M?
12–18M is for babies aged about one to one and a half, and 18–24M for about one and a half to two. After that, sizes are given in years, starting with 2–3Y.