How to Find the Right Kids Underwear Size Every Time
By Being Wear | Published: 2026-10-18
Category: Buying Guides
Stop guessing with kids underwear sizing. Follow these simple steps to measure your child, read size charts, and pick the right fit every time you shop.
Quick answer
To find the right kids underwear size, measure your child's waist and hips with a soft tape, then compare those numbers to the brand's size chart. For Being Wear kids boxers, waist measurement is the key number — and buying a bundle lets you try multiple sizes without extra cost.
Why sizing matters for kids underwear
Kids grow fast, and underwear that's too tight can cause red marks, discomfort, and even skin irritation. On the flip side, underwear that's too loose may bunch up or slide down, which is just as annoying. Getting the size right means your child can move, play, and sleep without distraction — and you won't have to replace pairs after a few washes.
Many parents rely on age labels alone, but age is a rough guide at best. Two kids of the same age can have very different waist and hip measurements. That's why measuring your child with a soft tape measure is the most reliable method, especially when shopping online for brands like Being Wear.
Step-by-step guide to measuring kids for underwear
- Measure the waist: Use a soft tape measure around the narrowest part of your child's waist — usually just above the belly button. Keep the tape snug but not tight. Write down the number in inches or centimeters. Common mistake: measuring over clothing or a diaper adds inches and leads to a too-loose fit.
- Measure the hips: Wrap the tape around the fullest part of the hips and bottom, about 7–9 inches below the waist. This is especially important for mid-length boxers that sit lower on the body. Checkpoint: if the hip measurement is larger than the waist, use the hip number to choose the size — the waistband will still stretch to fit.
- Compare to the brand's size chart: Every brand uses slightly different measurements. For Being Wear kids boxers, match your child's waist measurement to the size chart. If they fall between two sizes, size up for a relaxed fit or down for a snug one. Common mistake: relying on age labels. A 7-year-old may wear size 6 or 8 depending on their build. Always use actual measurements.
- Check the fit after the first wear: Have your child wear the underwear for a few hours. Look for red marks on the waist or legs, bunching fabric, or complaints of sliding down. The waistband should stay in place without digging in. If you see red marks, try the next size up. If the underwear twists or slides, try a size down or a style with a wider waistband like Being Wear's 40mm design.
Products that help you get the fit right
- kids boxer: Our mid-length boxers will keep young beings feeling good all day, every day. Crafted from our signature modal fabric, they're smooth, soft and breathable. A deep 40mm waistband, internal flatlock seams and tag-free design delivers less irritation and more all-day comfort. Available with or without pouch — pick what fits. The deep waistband and tag-free design reduce common fit issues like digging or itching, making it easier to tell if the size is truly right. Because the fabric is breathable, a snug fit won't cause overheating or sweat buildup.
- 3 kids boxers bundle: When you buy a Being Bundle (3 pack) you’ll save more. That’s more comfort, more colours, more ways to feel good, all with added savings. Our sets and bundles aren’t restricted to the same colour. Be free to mix and match. If you're between sizes or unsure, a bundle lets you buy two sizes at a lower per-pair cost. You can test the fit without committing to a full set of one size, and the mix-and-match colours keep kids happy.
