Baby Clothes Size Calculator
Find baby clothing size from age, weight, and height.
Returns US, UK, and EU sizes for newborn through 24 months with brand size comparison.
Your data stays in your browser. We do not store, collect, or transmit any information you enter.
Recommended Size
Baby clothing sizes vary by brand and region, but are generally based on weight and height/length.
US Baby Clothing Sizes:
| Size | Age | Weight | Height |
|---|---|---|---|
| Preemie | Premature | Up to 5 lbs (2.3 kg) | Up to 17 in (43 cm) |
| Newborn | 0–1 months | 5–8 lbs (2.3–3.6 kg) | 17–21 in (43–53 cm) |
| 0–3M | 0–3 months | 8–12 lbs (3.6–5.4 kg) | 21–24 in (53–61 cm) |
| 3–6M | 3–6 months | 12–16 lbs (5.4–7.3 kg) | 24–27 in (61–69 cm) |
| 6–9M | 6–9 months | 16–20 lbs (7.3–9.1 kg) | 27–29 in (69–74 cm) |
| 9–12M | 9–12 months | 20–24 lbs (9.1–10.9 kg) | 29–31 in (74–79 cm) |
| 12–18M | 12–18 months | 24–28 lbs (10.9–12.7 kg) | 31–33 in (79–84 cm) |
| 18–24M | 18–24 months | 28–30 lbs (12.7–13.6 kg) | 33–35 in (84–89 cm) |
| 2T | 2 years | 30–33 lbs (13.6–15 kg) | 35–37 in (89–94 cm) |
Metric conversions:
- Weight:
kg = lbs × 0.453592 - Height:
cm = inches × 2.54
Tips:
- When between sizes, always size up
- Different brands run small or large — check each brand"s specific chart
- Consider the season ahead when buying clothes for growing babies
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.