What does 6M mean in baby clothes?
In most brands, 6M means it fits up to 6 months — roughly the 3-to-6-month window — not from 6 months onward. Buying "6M" for a 6-month-old often means it's already outgrown.
How US baby sizes work
| Label | Typically fits | Weight (approx.) |
|---|---|---|
| NB (newborn) | 0–1 month | up to ~4 kg |
| 3M | 0–3 months | 4–5.7 kg |
| 6M | 3–6 months | 5.7–7.5 kg |
| 9M | 6–9 months | 7.5–9.3 kg |
| 12M | 9–12 months | 9.3–11 kg |
The label is the upper end of the range in most US brands (Carter's, Gerber and similar) — but not all brands agree, and babies vary hugely. The reliable numbers are weight and height on the label, not the month. When in doubt, size up: babies grow into clothes fast and out of them faster.
European sizes are simpler
European baby clothes are sized by height in centimetres: 56, 62, 68, 74, 80. A size 68 fits a baby up to 68 cm tall (roughly 4–6 months). Height sizing is less ambiguous than month labels — measure the baby and match the number.
| EU size (cm) | Approx. age |
|---|---|
| 56 | 0–2 months |
| 62 | 2–4 months |
| 68 | 4–6 months |
| 74 | 6–12 months |
| 80 | 12–18 months |
Frequently asked questions
Is 6M for a 6 month old baby?
Usually not — in most brands 6M fits up to 6 months (the 3–6 month window). A 6-month-old typically wears 9M.
What size does a 6 month old wear?
Usually 9M in US sizing, or EU size 68–74, depending on the baby's height and weight. Go by the cm and kg on the label.
How do European baby sizes work?
By height in centimetres: size 68 fits a baby up to 68 cm tall. Measure the baby and match the number.