How to Measure Yourself for a Suit (No Tailor Required)

Buying a suit online means the tape measure does the job a tailor usually would. Get five numbers right — chest, shoulders, sleeve, waist, and length and an off-the-rack pick from our men's suits collection will fit like it was made for you. Get them wrong, and even a well-made suit will look off. Here's exactly how to take each measurement yourself.

Quick Answer

You need five measurements to buy a suit online: chest, shoulder width, sleeve length, waist, and jacket length, plus inseam for the trousers. Use a soft fabric tape measure, keep it level and snug but not tight, and measure over a fitted shirt rather than bare skin or bulky layers for the most accurate result.

Table of Contents

• 1. What You'll Need
• 2. Chest and Shoulder Measurements
• 3. Sleeve and Jacket Length
• 4. Waist and Trouser Measurements
• 5. Self-Measuring vs. Professional Fitting
• 6. Common Measuring Mistakes
• 7. FAQ

What You'll Need

Three things: a flexible fabric tape measure (not the metal kind from a toolbox), a mirror, and ideally a second person to help — measuring your own back and shoulders accurately alone is genuinely difficult. Wear a fitted dress shirt or thin t-shirt while measuring; bulky layers add false inches everywhere they touch.

If you've already measured yourself for a jacket, you have a head start — the reference points carry over, and our jacket measuring guide covers the shoulder and sleeve technique in more depth.

Chest and Shoulder Measurements

Chest: Wrap the tape around the fullest part of your chest, under your arms and across your shoulder blades. Keep it level and snug, but leave room for one finger between the tape and your body — that's your breathing room.

Shoulder width: Measure from one shoulder seam edge to the other, straight across your back. This is the hardest number to fix after a purchase, so get a second opinion if you can, or check it against a jacket that already fits well through the shoulders. Builds vary enough that the same chest number can fit two people differently — FJackets' body style guide helps translate raw numbers into the right fit for your frame.

Sleeve and Jacket Length

Sleeve length: With your arm relaxed at your side and slightly bent, measure from the shoulder seam to just past your wrist bone, where you'd want the cuff to sit.

Jacket length: Measure from the base of your collar straight down to where you want the hem to fall — typically around the middle of your palm when your arm hangs naturally. Both numbers are easy to eyeball wrong. When in doubt, measure a jacket you already own and like the fit of, and match the new suit to those numbers instead of guessing from scratch.

Waist and Trouser Measurements

Waist: Measure around your natural waistline — roughly where your trousers currently sit, not where your belly button is. Keep the tape parallel to the floor.

Inseam: Measure from the crotch seam down to where you want the trouser hem to land, following the inside of your leg. These two numbers matter most if you're shopping for a wedding suit or another two-piece set with fitted trousers — a jacket can survive a small sizing miss better than trousers can.

Self-Measuring vs. Professional Fitting

Self-measuring works well for most buyers, but it helps to know when a professional fitting is the better call.

If your numbers land between two sizes or your build is asymmetrical, FJackets' suiting guide walks through how to choose between sizes and when a made-to-measure option is worth it.

Common Measuring Mistakes

• Measuring over a bulky sweater or jacket, which adds false inches to chest and shoulder numbers.
• Pulling the tape too tight, which shrinks the number and leads to a suit that fights you when you move.
• Measuring at the belt line out of habit instead of the natural waist, which throws off trouser sizing.
• Skipping a second measurement to confirm — numbers should match within a quarter inch when redone.
• Ignoring how suit style changes fit; a double-breasted jacket needs a little more chest room than a single-breasted cut, which our suit styles guide covers in more detail.

Save Your Numbers

Once you have your five measurements, save them somewhere permanent — your phone's notes app works fine. You'll want them every time you shop for formalwear going forward, not just this once.

Final Thoughts

A good suit fit comes down to five honest numbers, not guesswork. Measure over a fitted shirt, keep the tape level, and check questionable numbers against a jacket that already fits well. Once you trust your measurements, buying a suit online stops being a gamble.

Frequently Asked Questions

What's the most important measurement for buying a suit online?

Chest and shoulder width. Both are the hardest to fix after a purchase, so it's worth double-checking these two even if you rush the rest.

Can I measure myself accurately without help?

Mostly, yes. Chest, waist, sleeve, and inseam are easy to do solo. Shoulder width is the one measurement that benefits from a second person or a well-fitting reference jacket to check against.

Should I measure over a t-shirt or bare skin?

A thin, fitted t-shirt or dress shirt gives the most realistic number. Bare skin tends to under-measure slightly, while thick layers over-measure by an inch or more.

What if my measurements fall between two sizes?

For chest and shoulders, size up — it's easier for a tailor to take in a slightly large jacket than to let out a small one. For waist, go with the closer size, since trousers are generally simpler to adjust either way.

How often should I re-measure myself?

About once a year, or after any noticeable weight change. Body measurements shift more than most people expect, and a suit bought on old numbers rarely fits the same.