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Baby Clothing Size Converter
Enter your baby's length and weight to find the right US size, from preemie and newborn to 24 months, along with the matching European (50–92 cm) and UK sizes. Or convert a size label, such as EU 68 or UK 6–9 months.
Last updated:
I know the baby's
Lying flat, head to heel with the legs straight.
oz
months
Enter your values to see the result.
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How to use the Baby Clothing Size Converter
- Measure the baby's length lying flat, from the top of the head to the heel.
- Enter the weight in lb, lb + oz or kg, and the age in months if you like.
- Tick growing room to buy one size ahead, for gifts or the next season.
- Read the US, EU and UK sizes and the weight and length ranges.
- Or convert a label: switch to Size label and pick a US, UK or EU size.
US, EU and UK baby sizes side by side
| US size | Weight | Length | EU | UK |
|---|---|---|---|---|
| Preemie | up to 5 lb (2.3 kg) | up to 17 in (43 cm) | 44 | Early baby |
| Newborn | 5–8 lb (2.3–3.6 kg) | up to 21.5 in (55 cm) | 50 / 56 | Newborn |
| 0–3M | 8–12.5 lb (3.6–5.7 kg) | 21.5–24 in (55–61 cm) | 56 / 62 | 0–3 months |
| 3–6M | 12.5–16.5 lb (5.7–7.5 kg) | 24–26.5 in (61–67 cm) | 62 / 68 | 3–6 months |
| 6–9M | 16.5–20.5 lb (7.5–9.3 kg) | 26.5–28.5 in (67–72 cm) | 68 / 74 | 6–9 months |
| 9–12M | 20.5–24 lb (9.3–10.9 kg) | 28.5–30.5 in (72–77 cm) | 74 / 80 | 9–12 months |
| 12–18M | 24–27.5 lb (10.9–12.5 kg) | 30.5–32.5 in (77–83 cm) | 80 / 86 | 12–18 months |
| 18–24M | 27.5–30 lb (12.5–13.6 kg) | 32.5–34 in (83–86 cm) | 86 / 92 | 18–24 months |
Ranges follow typical US brand charts; each brand publishes its own and some run a size small or large. European sizes step every 6 cm, so one US size often straddles two EU numbers.
How to measure a baby for clothes
- Length: lay the baby on a flat surface, gently straighten the legs and measure from the top of the head to the bottom of the heel. Two people make this easier.
- Weight: use the latest reading from a checkup, or weigh yourself holding the baby and subtract your own weight.
- For sleepers and footed pajamas, length matters most. For bodysuits, weight and torso length matter most, because snaps that pull tight are uncomfortable.
Tips for buying baby clothes
- Babies typically double their birth weight by about 5 months and triple it by 12 months, so sizes change fast in the first year.
- For gifts, choose 3–6M or 6–9M rather than newborn, and think about the season the baby will wear it in.
- 100% cotton can shrink in the first hot wash; size up if the label doesn't say pre-shrunk.
- For safety, sleepwear should fit snugly or be flame resistant, and avoid drawstrings and loose decorations on baby clothes.
Frequently asked questions
How do EU baby sizes convert to months?
EU baby sizes are the maximum length in cm: 50 is newborn, 56 is about 0–2 months, 62 about 2–4 months, 68 about 4–6 months, 74 about 6–9 months, 80 about 9–12 months, 86 about 12–18 months and 92 about 18–24 months.
Should I choose baby clothes by age or by weight?
By weight and length. The month on the label is only an estimate, and babies grow at very different rates; a big 3-month-old may already wear 6–9M. When length and weight point to different sizes, choose the larger one.
What is the difference between 3M and 0–3M?
Some brands label sizes by the upper age (3M, 6M, 9M), others by range (0–3M, 3–6M). A 3M garment usually fits like 0–3M, but some brands' 3M runs closer to 3–6M, so check the weight range on the label.
How long do babies stay in newborn size?
Often only a few weeks. Newborn size fits about 5–8 lb (2.3–3.6 kg) and up to 21.5 in (55 cm). Many babies are born at 7–8 lb and move into 0–3M within the first month, so don't buy too much newborn clothing.
What size do preemies wear?
Preemie clothes fit babies up to about 5 lb (2.3 kg) and 17 in (43 cm). Some brands also make 'tiny baby' or 'early baby' sizes for under 3 lb. Preemie clothes often open fully at the front to fit around monitoring wires.
Is 24 months the same as 2T?
Not quite. 24M is cut with more room in the seat for a diaper and a shorter body, while 2T is made for walking toddlers, a little longer with more defined sleeves and legs. Many children wear both at around 2 years.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.
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