How to choose underwear without costly mistakes: find the right style, material and size

You may buy underwear in a hurry, but the wrong choice can bother you all day. A waistband that digs in, seams that show through your clothes or fabric that loses its shape after just a few washes can turn a bargain into an expensive purchase.

Pay particular attention to these three common pitfalls:

• Choosing a size based only on S, M or L. Sizes vary by brand, style and target customer. A 3XL from one brand may fit differently from a 3XL from another.
• Confusing marketing claims with verifiable properties. Words such as “antibacterial”, “moisture-wicking” or “extra comfortable” mean little without information about the composition, construction and care requirements. If a brand mentions a particular effect, this is a claim from the product description or based on the brand’s own research; it is not an established result for every wearer.
• Ignoring the pack size and care instructions. A multipack of underwear is practical, but only worthwhile if the fit and washing instructions suit your routine. Not every style can go in the tumble dryer.

The key points when comparing underwear

1. Fit and body measurements

Before ordering, check the size chart and compare it with your waist and hip measurements. For women’s underwear, hip measurements are often the deciding factor. For men’s underwear, the focus is usually on the waist, the height of the waistband and the amount of room at the front.

• Women’s thongs and thongs use very little fabric and may therefore be less forgiving when the size is not right.
• Women’s briefs, bikini briefs and hip briefs offer more coverage and may be more comfortable for everyday wear.
• Men’s boxers, boxer briefs and trunks mainly differ in leg length, leg opening and support.
• A low waist, such as with low-rise trunks, can work well under low-rise trousers, but may be less suitable if you want more coverage around the stomach.

Also pay attention to the sizing information for larger sizes. Some product pages show a style name with 3XL or 4XL, while the chart does not list every size. Always check the current product page before completing your purchase.

2. Material: look beyond “soft”

Cotton underwear feels familiar to many people and is suitable for an everyday wardrobe. Elastane provides stretch and helps the style fit more closely. A composition such as 90% cotton and 10% elastane offers a different level of stretch from a product made with polyester or modal.

Practical differences:

• Cotton with elastane: a familiar everyday basic with room for movement.
• Modal: often chosen for its smooth, soft feel. Always check the exact composition.
• Polyester with cotton and elastane: can create a sturdy, flexible fabric, as with some trunks.
• Seamless underwear: may be less visible under close-fitting clothing. However, pay attention to the edge and waistband; even a seamless style can roll up if the size is not right.

A product description may mention properties such as breathable, moisture-wicking or antibacterial. Treat these as information from the seller. A claim based on the brand’s own research or on the product description is not automatically a guarantee for every user.

3. Care and durability

Wash underwear according to the care label. Many styles are machine-washable, but the temperature and drying method vary.

• Wash delicate or seamless styles at the recommended temperature.
• Do not use bleach if it is not permitted.
• Avoid the tumble dryer for products that may lose their elasticity.
• A low-heat drying setting is only suitable when the product information explicitly says so.

An elasticated waistband, sturdy seams and clear washing instructions are verifiable indications of practical use. They do not say exactly how long a product will last, as this also depends on how often it is worn, the washing temperature and the detergent used.

Our recommendations by user type

Suitable for: Budget-conscious beginners

Utree women’s underwear 3-pack

Why it suits this profile: A three-colour multipack is practical if you want to replenish your everyday underwear without choosing several individual styles. The product page lists modal, stretch and sizes M to XL.

How this product avoids the pitfall

The composition, size options and packaging are clearly stated. However, check that the listed fit suits your hip measurement.

Main benefit & advantages

3-pack, stretchy fabric and a style with full coverage according to the product description.

Suitable for: Shoppers looking for premium quality

Calvin Klein 3-Pack Strings - Icon Logo - White 3XL

Why it suits this profile: If you are looking for branded underwear with minimal coverage, you get three white thongs with a logo waistband and a composition of 90% cotton and 10% elastane.

How this product avoids the pitfall

The fabric composition and care information are specific. Pay particular attention to the size chart: the product name mentions 3XL, while the displayed chart means you need to check before buying.

Main benefit & advantages

3 items, cotton-elastane fabric and a design that, according to the description, remains discreet under clothing.

Suitable for: Specific use & intensive users

Reebok RBK Sports Trunks Baird

Why it suits this profile: The 5-pack is aimed at people who change underwear frequently, exercise or want enough pairs for several working days in a row. The product description mentions an elasticated waistband and a supportive fit.

How this product avoids the pitfall

The packaging makes the number of items clear. Check the care instructions before use: do not bleach and do not tumble dry.

Main benefit & advantages

5-pack, flexible waistband and black, grey and white colours according to the product details.

Suitable for: Minimalist everyday wearers

Calvin Klein 3 Pack Low Rise Trunks - Icon Cotton Stretch

Why it suits this profile: These trunks are designed for anyone looking for a close-fitting, low-rise style. The product page lists cotton with elastane, a 3-pack and a seamless Infinity Bond waistband.

How this product avoids the pitfall

The construction and care instructions are described clearly. The low-rise cut is not a universal solution: choose this style only if the height suits your clothing and preferences.

Main benefit & advantages

3-pack, stretch fabric and a waistband without traditional seams according to the product description.

How to make a practical choice

Follow this order when comparing underwear online:

1. Choose the style first: thong, brief, bikini brief, trunk or boxer brief.
2. Measure your waist and hips: use the size chart for the specific product, not just your usual clothing size.
3. Check the fabric: look at the cotton, modal and polyester content, as well as the percentage of elastane.
4. Look at the pack size: compare a single pair with a multipack based on how often you will wear it and the price per item.
5. Read the washing instructions: especially if you normally use a tumble dryer.
6. Check the colour and transparency: white underwear is versatile, but may show through light-coloured clothing. Choose a style that suits your clothes and the coverage you want.

Frequently asked questions about underwear

How often should you replace your underwear?

There is no fixed timeframe. Replace a pair when the elastic becomes loose, the fabric starts to thin, the seams come undone or the fit changes. If you change underwear daily and use a multipack, wear is spread more evenly across several pairs.

Is cotton always the right choice for everyday underwear?

Cotton is a practical choice for many wearers, but it is not automatically right for everyone. Check the full composition. A little elastane can improve the fit, while modal or a synthetic blend may offer a different feel and require different care.

What is the difference between trunks and boxer briefs?

Trunks usually have shorter legs and a closer fit. Boxer briefs can be longer or looser. Look at the leg opening, rise and amount of stretch. For everyday wear, the most important thing is that the style does not roll up or dig in as you move.