How to Handle Sock and Underwear Sizing Between Sizes

Quick answer

When you're between sizes, size up for underwear and size up for socks if the smaller size leaves marks or restricts movement. If the larger size slips or bunches, try a different style or fabric rather than forcing a size. The right choice depends on whether the problem is tightness or looseness.

You checked the size chart, but your measurements land between two sizes. Do you go up or down? The answer isn't the same for every garment, and guessing wrong means discomfort all day.

This guide walks you through a simple diagnosis: identify the symptom, understand the likely cause, take corrective action, and know when to stop adjusting and choose a different option entirely.

Why between-sizes happens more in socks and underwear

Socks and underwear are knit garments, so they rely on stretch and recovery rather than precise tailoring. Two people with the same foot length can have very different foot widths and instep heights, which affects how a sock fits. Similarly, waist and hip measurements don't tell the whole story for underwear—rise, leg opening, and fabric stretch matter just as much.

Because sizing charts use a few key measurements, they can't capture every body variation. That's why being between sizes is common and why the right call depends on the specific fit problem you're experiencing.

• Measure your foot length and width, plus your waist and hips, at the end of the day when feet and body are slightly larger.
• Check the fabric content: more stretch means more forgiveness between sizes.

Diagnose sock fit: too tight vs. too loose

If a sock leaves deep marks on your ankle or calf, feels restrictive around the arch, or makes your toes curl, it's too tight. This can restrict circulation and cause discomfort during long wear. If the sock slides down inside your shoe, bunches at the heel, or twists around your foot, it's too loose.

For socks, sizing up is usually the safer choice when you're between sizes, especially if you have wider feet or a high instep. A slightly larger sock can still stay in place thanks to elastic bands, but a too-small sock will never stretch enough to be comfortable. However, if the larger size still slides, the issue may be the sock's construction rather than its size.

• Try socks on with the shoes you'll wear most often—shoe volume changes how a sock fits.
• If one foot is larger, always fit the larger foot.

Diagnose underwear fit: waistband, rise, and leg opening

Underwear that digs into your waist, leaves red marks, or causes chafing is too small. If the waistband gaps, the fabric bunches under clothing, or you constantly need to adjust, it's too large. The waistband is often the first place to show a sizing problem, but the leg opening and rise can also cause issues.

When between sizes in underwear, sizing up is generally better because a slightly looser fit is more comfortable and less likely to cause irritation. But if the larger size feels baggy or rides up, consider a different cut or a fabric with more stretch. For example, a mid-length boxer with a deep waistband can solve waistband digging without going up a size.

• Check the waistband width: wider bands distribute pressure better and can make a smaller size feel more comfortable.
• Look for flatlock seams and tag-free designs if irritation is your main problem.

When to stop adjusting and switch options

If you've tried both sizes and neither works, the problem isn't the size—it's the style or fabric. For socks, if quarter socks slide down but crew socks stay put, switch to a crew style. For underwear, if boxers ride up but briefs don't, try a different cut. Bundles can be a low-risk way to test multiple colors or styles without committing to a full pack of one option.

Stop adjusting when you've spent more than a few days uncomfortable in a size. Discomfort that persists after one wash and wear cycle is a sign to return or repurpose the item and try a different product.

• Give new socks and underwear one wash and wear cycle before deciding they don't fit.
• If you're consistently between sizes, look for brands that offer more granular sizing or styles with adjustable features.

Sizing diagnosis: symptom, cause, action, and stop point

• Symptom: Sock leaves deep marks or feels restrictive: Likely cause: The sock is too small, especially around the calf or arch. Corrective action: Size up. If the next size still marks, look for a style with a wider leg or more stretch. Stop if two sizes both leave marks—switch to a different sock style or brand.
• Symptom: Underwear waistband digs in or leaves red marks: Likely cause: Waistband is too tight or too narrow. Corrective action: Size up, or choose underwear with a wider waistband like a 40mm band. If the larger size gaps, try a different cut. Stop if you've tried two sizes and still have marks—consider a different rise or fabric.
• Symptom: Sock slides down or bunches in shoe: Likely cause: Sock is too large or has lost elasticity. Corrective action: Size down if you're between sizes. If it still slides, the sock's construction may not suit your foot shape. Stop if sizing down feels tight—try a different sock height or brand.
• Symptom: Underwear rides up or bunches: Likely cause: Underwear is too large or the cut doesn't match your body. Corrective action: Size down if between sizes, or switch to a different style (e.g., boxer vs. brief). Stop if the smaller size feels restrictive—try a different fabric with more stretch.

Product facts to guide your choice

• kids boxer: Crafted from 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 flatlock seams reduce digging and chafing, which are common between-size problems. The pouch option lets you choose a fit that works for your body.
• crew sock: Sitting around mid-calf they deliver everyday feels with effortless style. We’ve added a padded undersole for extra cushioning and a light knit upper. The padded undersole adds cushioning without bulk, and the light knit upper helps prevent tightness across the top of the foot—useful if you're between sizes and want a secure but not restrictive fit.
• 3 kids quarter socks bundle: Our bundles aren't restricted to the same colour. Be free to mix and match. From daily wear to daily workouts, our bamboo socks do it all — and feel great doing it. Soft, breathable and naturally moisture-wicking. If you're unsure which size works, a bundle lets you test multiple pairs without committing to a single color or style. Bamboo's moisture-wicking properties help keep feet comfortable if you're between sizes and prone to sweating.

Between sizes doesn't have to mean settling for discomfort. Diagnose whether the issue is tightness or looseness, then size up for a safer fit in most cases. If two sizes both fail, the problem is the style—not you. Use bundles to test options, and don't be afraid to switch cuts or fabrics until you find what works.