Columbia
Columbia Youth Baselayer Midweight Long John
Columbia Youth Baselayer Midweight Long John
📏 View Size Guide
Sizing for Columbia Youth Baselayer Midweight Long John
Columbia youth / unisex bottoms
Columbia publishes separate boys’ and girls’ reference charts. Both are shown for this unisex product. Body measurements in cm, converted from official inch values at 2.54 cm per inch. Check the product’s own fit advice.
Swipe across the table if needed to see every measurement.
| Manufacturer chart | Letter size | Approx. age | Waist (cm) | Hips (cm) |
|---|---|---|---|---|
| Boys | XXS | 4-5 years | 53.3–54.6 | 58.4–61 |
| Boys | XS | 6-7 years | 55.9–59.7 | 63.5–67.3 |
| Boys | S | 8 years | 62.2 | 70.5 |
| Boys | M | 10-12 years | 64.8–67.3 | 73.7–77.5 |
| Boys | L | 14-16 years | 71.1–74.9 | 81.3–85.1 |
| Boys | XL | 18 years | 78.7 | 88.9 |
| Girls | XXS | 4-5 years | 53.3–54.6 | 58.4–61 |
| Girls | XS | 6-7 years | 55.9–59.7 | 63.5–69.8 |
| Girls | S | 8 years | 61.6 | 72.4 |
| Girls | M | 10-12 years | 63.5–66 | 76.2–81.3 |
| Girls | L | 14-16 years | 71.1–76.2 | 86.4–91.4 |
| Girls | XL | 18 years | 81.3 | 96.5 |
Official manufacturer source · Checked 28 October 2026
Only sizes offered in the product’s size selector can be ordered. Charts may show additional manufacturer sizes.
How to measure
Use a soft tape measure. Measure chest around the fullest point, waist at the natural waistline and hips at the widest point. Measure height without shoes. Follow the manufacturer’s method for inside leg and accessories.
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Cozy Mole Enterprise LTD says:
The Columbia Youth Baselayer is the junior version of Columbia'a highly successful Omni-Heat baselayer range for adults. This midweight long john uses Omni-Heat technology to make sure you stay warm. The reflective micro-dot layer on the underside retains the heat your body generates, whilst allowing excellent levels of breathability. Furthermore, the Omni-Wick fabric ensures that any moisture generated is quickly wicked away from the skin and evaporated. A top quality junior baselayer. Matching long sleeve top also available.
Available in Black or Bright Rose. Unisex sizing. Baselayers should be worn in contact with the skin for best results, so this needs to be balanced with any desired 'growing room'.
Manufacturer's Comments on this product:
- Fabric: 85% polyester; 15% elastane; 170g
- Omni-Heat™ thermal reflective
- Omni-Wick™ moisture management
- Breathable
- Anti-microbial
- 4-way comfort stretch
