Men’s Underwear Size Guide: How to Choose the Right Size

A men’s underwear size guide should make buying online easier, not more complicated. Start with your current body measurement, compare it with the official Gigo Size Guide, and use the size shown there as your starting point. You do not need to memorize a chart or guess from the size you wear in another brand.

Choosing the right men’s underwear size is mainly about three things: knowing your measurement, checking the current size chart, and then choosing the cut you actually want to wear. Fabric, stretch and construction can change how two garments feel, but they should not turn sizing into guesswork.

If you are new to Gigo, the current Size Guide is the source of truth. If you still have a question about one specific product after checking your measurement, contact the Gigo team and we can help you look at the construction and fit details of that style.

How Do I Know What Size Underwear to Buy?

Measure your body where the underwear waistband normally sits and compare that number with the current Gigo Size Guide. That gives you the most reliable starting size for Gigo underwear.

Do not begin with the letter size you usually buy from another brand. Sizing systems can differ, and the same letter can represent different measurement ranges.

If you want the measuring process step by step, use our separate guide: How to Measure Men’s Underwear Size. This article focuses on the next decision: how to use that measurement to choose what to buy.

Use the Current Gigo Size Guide Instead of Memorizing Numbers

We intentionally recommend checking the live Size Guide instead of relying on measurements copied into a blog post. Size ranges do not change often, but they can be updated. Keeping one official source helps prevent old numbers from creating confusion.

The process is simple:

1. Know your current body measurement.
2. Open the Gigo Size Guide.
3. Find the size that corresponds to your measurement.
4. Choose the underwear cut and product you want in that size.

That is enough for most purchases. You do not need to create extra rules for every fabric, color or silhouette before ordering.

What If I Am Between Two Underwear Sizes?

If your measurement falls between two Gigo sizes or directly on a shared boundary, start with the larger size. That is the same recommendation used across our sizing and fit guides.

Do not automatically size down just to create a tighter or more revealing look. Let the cut, rise, pouch, coverage and design create the silhouette.

If this is the exact situation you are dealing with, read Between Two Underwear Sizes? How to Decide.

Does Fit Preference Change the Size I Should Buy?

Your fit preference matters, but it should not replace the size chart. Start with the size that matches your measurement.

Then choose the garment style according to how you like underwear to look and feel. A brief, trunk and jockstrap can all feel different in the same size because they use different amounts of fabric and different construction.

If you want less thigh fabric, compare Men’s Briefs. If you prefer short-leg coverage, compare Men’s Trunks. If you want an open-back construction, explore Men’s Jockstraps.

The size establishes the starting point. The cut creates the experience.

Why Can Two Garments in the Same Size Feel Different?

Two products can share the same size and still feel different because of fabric stretch, elastic recovery, pouch construction, waistband design, rise, seams and coverage.

That does not mean you should ignore the Size Guide. It means the chart gives you the correct starting size, while the product construction explains why one silhouette may feel different from another.

Read the product description and look at the front and back photos for the specific piece you are considering. If one particular garment raises a question after you check your measurement, that is the point where contacting us can be useful.

Size, Cut and Fit Are Different Decisions

Keeping these three ideas separate makes online underwear shopping much easier.

• Size starts with your body measurement and the current Gigo Size Guide.
• Cut is the garment structure: brief, trunk, jockstrap, G-string or another silhouette.
• Fit is how that specific size and cut feel once they are on your body.

That distinction is important because a problem in one area does not always mean the entire size is wrong. If the waistband feels right but the pouch, thighs or rear coverage do not, another cut or construction may be the better answer.

For a complete fit check after you receive the garment, use How Should Men’s Underwear Fit?.

Should I Use My Pants Size to Choose Men’s Underwear?

Your pants size can be a reference, but it should not replace an actual body measurement. Different brands and garments can label sizes differently, and the position where pants sit may not be identical to where you wear your underwear waistband.

If you are unsure, measure your body and compare that number directly with the current Gigo chart. That removes more uncertainty than trying to convert another brand’s label.

Should I Size Down for More Support?

No. More tightness does not automatically create better support.

Support depends on the relationship between the pouch, waistband, fabric, seams and overall construction. Choose your size from your measurement, then choose a cut designed to give you the amount of support and coverage you prefer.

If the front is the only area that feels wrong, our men’s underwear pouch fit guide explains why changing the entire size is not always the first solution.

How to Choose Men’s Underwear Size Before You Order

For most shoppers, this short checklist is enough:

• Know your current body measurement.
• Compare it with the current Gigo Size Guide.
• If you are between sizes or on a shared boundary, start with the larger size.
• Choose the cut you actually want instead of changing size to force a different silhouette.
• Read the specific product details for fabric, rise, pouch and coverage.
• If a specific product still raises a question, contact the Gigo team before ordering.

That keeps the decision practical. The goal is to make buying underwear online feel more predictable, not to give you dozens of reasons to doubt the size you already measured.

Frequently Asked Questions About Men’s Underwear Sizing

How do I know what size underwear to buy?

Measure your body where the waistband normally sits and compare that measurement with the current Gigo Size Guide. Use the size shown there as your starting point.

How do I choose men’s underwear size online?

Start with your body measurement, check the brand’s current size guide and then choose the cut you want. For Gigo, use the official Size Guide rather than relying on another brand’s letter size.

What if I am between two sizes?

If your measurement falls between two Gigo sizes or directly on a shared boundary, start with the larger size.

Can fabric change how the same size feels?

Yes. Stretch, recovery, lining, waistband construction, seams and cut can change the feel of a garment. That is why two products in the same size can feel different without requiring a different sizing system.

Should I buy a smaller size if I want a tighter look?

No. Choose the size that matches your measurement and use the cut, rise and coverage to create the look you want.

What if I still have a question about a specific Gigo product?

Check the Size Guide first. If the measurement is clear but you are unsure how a particular product’s construction may feel, contact the Gigo team and we can help you review that specific style.

Choose the Size, Then Choose the Underwear You Want

Online sizing does not need to be the stressful part of buying underwear. Know your measurement, use the current Size Guide and let the garment design handle the rest.

Explore Gigo Men’s Underwear to compare briefs, trunks, jockstraps and other silhouettes after confirming your starting size.