Men’s Underwear Size Chart: How to Read It Online

A men’s underwear size chart connects your body measurement with the size used by a specific brand. To read one correctly, measure your waist where your underwear waistband normally sits, keep the tape level without pulling it tight, and match that number to the appropriate range in the brand’s chart.

Do not choose a size only because it is the letter you normally buy. A medium from one brand can represent a different waist range from a medium somewhere else, which is why your current body measurement should come first.

What Does a Men’s Underwear Size Chart Show?

A men’s underwear size chart translates a body measurement into labels such as S, M, L, XL and 2XL. Each size normally represents a range rather than one exact waist measurement.

The current Gigo Size Guide uses these ranges for underwear and other lower-body garments:

Gigo Size	Waist Inches	Waist Centimeters
S	27–31 in	68–80 cm
M	31–34 in	80–86 cm
L	34–36 in	86–92 cm
XL	36–39 in	92–98 cm
2XL	39–41 in	98–104 cm
3XL	41–43 in	104–110 cm
4XL	43–46 in	110–116 cm
5XL	46–48 in	116–122 cm

These ranges apply to Gigo briefs, trunks, jockstraps, G-strings, swim briefs, swim trunks, shorts and pants. Tops and upper-body garments use chest measurements instead, so always check that you are reading the correct section of the Gigo Size Guide.

Body Measurements vs. Garment Measurements

Before using any underwear size chart, determine whether the numbers describe your body or the garment itself.

Gigo uses body measurements. If your waist measures 33 inches, you locate 33 inches in the waist column and choose the size containing that measurement.

A garment measurement is different. Measuring a pair of underwear flat across the waistband gives you the width of the garment in that position, not your full body circumference. Elastic underwear may also look considerably smaller when lying flat than it does while being worn.

Do not compare the flat width of an unstretched waistband directly with the waist measurement in the Gigo chart.

How to Measure Your Waist for Underwear

For Gigo underwear and other lower-body styles, waist circumference is the main sizing reference.

1. Stand naturally with your abdomen relaxed.
2. Use a soft measuring tape.
3. Wrap it around the area where you normally wear your underwear waistband.
4. Keep the tape parallel to the floor.
5. Let it rest against your body without pulling it tight.
6. Breathe normally and record the measurement.

For many men, this point is around the lower waist, typically just above the hip bones. The exact position can vary slightly depending on where you normally wear your underwear.

Do not hold in your abdomen to obtain a smaller number, and do not leave the tape loose. The measurement should represent how your body normally rests.

Do Not Use Your Pants Size as Your Underwear Size

Your pants label can be useful context, but it should not replace an actual waist measurement.

A pair of pants labeled 32 does not necessarily mean your body currently measures exactly 32 inches where your underwear waistband sits. Trouser rise, brand sizing and manufacturing tolerances can all affect the number on the label.

Measure your body first and use the chart from the underwear brand you are buying.

How to Match Your Measurement to the Gigo Size Chart

1. Choose inches or centimeters

Use the same unit from beginning to end. For the USA store, Gigo displays inches first and centimeters as an additional reference.

If your measuring tape includes both units, there is no need to perform your own conversion.

2. Find your measurement in the waist column

Locate your actual measurement inside the range.

For example:

• A 33-inch waist falls within 31–34 inches: Gigo M.
• A 35-inch waist falls within 34–36 inches: Gigo L.
• A 37-inch waist falls within 36–39 inches: Gigo XL.
• A 40-inch waist falls within 39–41 inches: Gigo 2XL.

3. Check whether you are on a shared boundary

Some Gigo ranges meet at the same measurement. For example, 31 inches is the upper boundary of S and the beginning of M.

Under the current Gigo sizing recommendation, if your measurement falls between two sizes or directly on a shared boundary, start with the larger size.

For a more detailed explanation of these boundary cases, read Between Men’s Underwear Sizes? How to Decide.

Why Size Letters Are Not Universal

S, M, L and XL are convenient labels, but they are not standardized measurements across every underwear brand.

A medium can represent one waist range at Gigo and another range somewhere else. That means transferring your usual letter size from another company can lead to a poor fit even if you have worn that letter for years.

The safer sequence is:

1. Measure your body.
2. Check the current brand-specific chart.
3. Select the range containing your measurement.
4. Then consider how the particular cut should feel.

Size and Cut Are Two Different Decisions

The size chart tells you where to start. The cut determines how that size is distributed around your body.

A brief, trunk and jockstrap in the same Gigo size can feel different because they use different amounts of fabric and place their openings, straps and coverage in different areas.

Briefs

Briefs leave the upper thigh uncovered. After choosing your waist size, pay attention to the pouch, leg openings and rear coverage.

Browse the Gigo Men’s Briefs collection to compare different brief constructions.

Trunks

Trunks add a short leg around the upper thigh. The waist measurement still determines your starting size, but thigh shape and leg-opening construction can affect how the garment feels.

Explore the Gigo Men’s Trunks collection to compare silhouettes.

Jockstraps

Jockstraps use a waistband, pouch and rear straps rather than a full back panel. Start with the same waist measurement used for other Gigo lower-body garments.

Do not automatically size down because the back is open. Minimal rear coverage is part of the cut, not a different sizing system.

Compare styles in the Gigo Men’s Jockstraps collection.

Common Men’s Underwear Size Chart Mistakes

Using the size you always buy

Your usual size is not enough if you are switching brands or your body measurements have changed. Check the current chart.

Measuring the underwear instead of your body

The Gigo chart uses body measurements, so measure your waist rather than comparing the chart with the flat waistband of another garment.

Measuring the wrong part of your waist

Measure where your underwear waistband normally sits rather than automatically choosing the narrowest part of your torso.

Pulling the tape too tightly

The tape should touch your body without compressing it. Making the number artificially smaller can push you toward an unnecessarily tight size.

Mixing inches and centimeters

Choose one measurement system and follow that column. Do not compare an inch measurement with the centimeter column or rely on approximate mental conversions.

Assuming every cut should feel identical

The waist measurement gives you a starting size, but briefs, trunks and jockstraps distribute coverage differently.

If the waistband itself is the problem, read our men’s underwear waistband fit guide. If pressure or ride-up happens mainly around the thighs, see our leg-opening fit guide.

How to Confirm the Fit After Your Underwear Arrives

The size chart gets you to the recommended starting point. Movement tells you whether the particular cut is working.

After trying on the garment, perform a simple movement check:

1. Walk normally.
2. Sit down and stand back up.
3. Lift each leg slightly.

A well-fitting garment should remain stable without requiring constant adjustment.

Look for:

• a waistband that stays in place without excessive pressure;
• front support without uncomfortable compression;
• leg openings that follow the body without digging in;
• rear coverage or straps that remain in their intended position;
• and enough freedom to sit and walk normally.

If everything feels tight at once, reconsider the size. If your waist feels correct but only one area causes trouble, the cut may be a better place to investigate.

For a broader sizing discussion, you can also read How to Choose the Perfect Size of Men’s Underwear.

Quick Size Chart Checklist

Before Ordering	What to Do
Measurement source	Use your body, not an old garment
Measurement point	Where your underwear waistband normally sits
Tape tension	Flat and comfortably fitted, not tight
Units	Use one column consistently
Brand	Use the Gigo chart for Gigo products
Between two sizes	Start with the larger Gigo size
After delivery	Confirm the fit while walking, sitting and moving

Frequently Asked Questions

What measurement determines Gigo men’s underwear size?

For Gigo briefs, trunks, jockstraps and other lower-body garments, use your waist circumference where the waistband normally sits.

Should I use my pants size to buy underwear?

No. Your pants label may not equal your current body measurement. Measure your waist and compare it with the brand-specific underwear size chart.

Are Gigo size-chart numbers body measurements?

Yes. The Gigo lower-body chart uses body measurements rather than the unstretched dimensions of the garment.

What if my measurement is between two Gigo sizes?

The current Gigo Size Guide recommends starting with the larger size when you fall between two sizes or directly on a shared boundary.

Is a medium the same across every underwear brand?

No. Letter sizes are brand-specific. Compare your actual waist measurement with the chart of the brand you are purchasing.

Should briefs, trunks and jockstraps use different size charts?

At Gigo, these lower-body styles begin with the same waist-based chart. Their cuts can feel different, however, because coverage, leg openings, pouch construction and straps vary.

Read the Numbers Before Choosing the Letter

A men’s underwear size chart is useful only when you start with the correct measurement. Measure your waist where the waistband normally rests, keep the tape level and comfortable, and match that number with the current Gigo range instead of relying on the size you usually buy elsewhere.

Once you know your starting size, choose the cut that gives you the coverage and feel you want. The chart answers which size; the garment construction determines how that size fits.