Men’s Suit Size Guide: How to Measure Yourself and Find the Perfect Fit Online

Buying a suit online has never been easier, but it still comes with one major hurdle: figuring out your size. A $1,000 suit that fits poorly will always look worse than a $200 suit that fits perfectly. Fit is everything.

If you’ve ever looked at a suit size like “42R” or “38S” and wondered what it actually means, you’re not alone. In this comprehensive men’s suit size guide, we’ll break down exactly how suit sizing works, how to measure yourself at home, and how to ensure your next online purchase fits like it was custom-tailored.

Understanding Suit Sizes

A standard men’s suit jacket size consists of two parts: a number and a letter (e.g., 40R).

1. The Number (Chest Size)

The number in a suit size refers to your chest measurement in inches. If your chest measures 40 inches around its widest point, you are generally a size 40.

2. The Letter (Jacket Length)

The letter indicates the length of the jacket and the sleeves. It is based on your overall height:
* S (Short): Typically for men under 5’7″. The jacket body and sleeves are cut shorter.
* R (Regular): Typically for men between 5’8″ and 6’0″. This is the standard length.
* L (Long): Typically for men between 6’1″ and 6’3″. The jacket body and sleeves are longer.
* XL (Extra Long): Typically for men 6’4″ and taller.

How to Measure Yourself at Home

You don’t need a professional tailor to find your size. All you need is a soft cloth measuring tape and ideally, a friend to help (though you can do it yourself in front of a mirror).

The Chest Measurement

This is the most important measurement for a suit jacket or blazer.
1. Stand up straight and breathe normally.
2. Wrap the measuring tape around the widest part of your chest, just under your armpits and across your shoulder blades.
3. Keep the tape level and snug, but not uncomfortably tight. You should be able to slip one finger under the tape.
4. If your measurement falls between sizes (e.g., 39 inches), it’s generally best to round up to the next even number (size 40) for a comfortable fit.

The Over-Arm Measurement

This helps ensure the shoulders of the jacket will be wide enough.
1. Keep your arms relaxed at your sides.
2. Wrap the tape around the broadest part of your chest and shoulders, encompassing your arms.
3. If this measurement is 7 or more inches larger than your chest measurement, you may need to size up your jacket.

The Waist Measurement (For Trousers)

Suit pants are sized differently than casual jeans. Your jeans size is likely vanity-sized (meaning a size 34 jean might actually measure 36 inches).
1. Measure around your natural waistline, typically right around your belly button or just below it, where you actually wear your dress pants.
2. Insert one finger between the tape and your body for comfort.
3. This true measurement is your suit pant size.

The Inseam Measurement

1. Wear a pair of shoes similar to what you’ll wear with the suit.
2. Measure from the lowest part of your crotch seam down the inside of your leg to where you want the pants to end (usually right at the top of the shoe heel).

The Suit Size “Drop”

When buying a complete suit (jacket and pants sold together), manufacturers use a standard “drop.” The drop is the difference between the jacket size and the pant waist size.

In the United States, the standard drop is 6 inches.
* If you buy a size 40R suit, it will come with size 34 pants (40 – 6 = 34).
* If you buy a size 44L suit, it will come with size 38 pants (44 – 6 = 38).

If your body proportions don’t fit the standard 6-inch drop (for example, you have a 42 chest but a 32 waist), you should look for “suit separates,” where you can buy the jacket and pants individually.

Use Our Coat Size Estimator

If you’re still unsure about your size, we’ve made it incredibly easy. You don’t even need a measuring tape.

Simply use our proprietary Coat Size Estimator. By entering your height, weight, and general body shape, our algorithm will accurately predict your ideal jacket and pant size. It’s the fastest way to shop for sport coats, blazers, and suits with confidence.

Once you know your size, explore our full collection of suits and formalwear to find your perfect fit today.