What is the most important part of a suit's fit?

The shoulders. The shoulder seam should end where your own shoulder ends, with the sleeve hanging cleanly. Shoulders are difficult and expensive to alter, so a suit that fits in the shoulders is worth buying and tailoring, while one that does not is usually best left in the store.

How much shirt cuff should show below a suit sleeve?

A common guideline is about a quarter to half an inch of shirt cuff showing when your arms hang naturally at your sides. It creates a neat line and protects the jacket sleeve from wear. Sleeve length is one of the easiest and most affordable alterations.

Should suit trousers touch my shoes?

That is a matter of preferred break, the fold where the trouser meets the shoe. A slight or no break gives a clean, modern look, while a medium or full break is more traditional. Whichever you choose, the trousers should not pool in heavy folds around the ankle.

How a Suit Should Fit: A Head-to-Toe Guide

A modest suit that fits well looks better than an expensive one that does not. Fit is what makes a suit look sharp, comfortable and deliberate, and it is often the difference between looking dressed up and looking as if you borrowed someone else's clothes. The good news is that you do not need to be an expert. With a clear checklist and a good tailor, most men can get an off-the-rack suit to look close to made for them.

Start with the shoulders

The shoulders are the foundation. They are also the hardest part to alter, so judge them first.

The shoulder seam should end where your shoulder ends, the point where the arm meets the body.
The sleeve should hang straight from the shoulder without a dent or ripple at the top of the arm.
Too wide: the shoulder pad extends past your arm, creating a step or a dent below it.
Too narrow: the sleeve head bulges and the fabric pulls across the upper arm.

If the shoulders do not fit, move on to another size or another brand. No reasonable alteration will fix them.

The collar

The jacket collar should rest against your shirt collar, which in turn should rest against your neck.

A gap between jacket collar and shirt collar at the back of the neck, often called collar gap, usually indicates a posture or cut mismatch. A skilled tailor can sometimes improve it, but it is worth noticing before you buy.
About a quarter to half an inch of shirt collar should show above the jacket collar at the back.

The chest and buttoned waist

Button the jacket (the top button on a two-button jacket, the middle on a three-button) and look in the mirror.

The lapels should lie flat against your chest.
The front should close smoothly. An "X"-shaped pull radiating from the button means the jacket is too tight.
Excess fabric billowing at the sides or back means it is too loose.
You should be able to slide a flat hand inside the buttoned jacket comfortably, but not a fist.

Waist suppression, how much the jacket narrows at the waist, is easy for a tailor to adjust in either direction within limits.

Jacket length

Traditional guidance is that the jacket should cover your seat. Many current suits are cut slightly shorter, but a jacket that ends well above the seat can make legs look disproportionately long, and one that is too long can make legs look short.

A simple test: with your arms relaxed at your sides, the hem of the jacket usually falls around the middle of your hand or at the knuckles. Jacket length cannot realistically be changed much, so treat it as a buying decision.

Sleeves

Sleeve length is one of the most noticeable details, and one of the easiest to fix.

With arms hanging naturally, about a quarter to half an inch of shirt cuff should show.
The sleeve should end around the point where the wrist meets the hand.
Sleeve width should follow the arm without clinging.

Note that jackets with working buttonholes on the cuff (sometimes called surgeon's cuffs) are harder to shorten from the cuff end, so get the sleeve length right before buying if the buttonholes are already cut.

The trousers

Waist and seat

The trousers should sit comfortably at your natural waist or just below, without a belt doing the work of holding them up. The seat should follow your shape without pulling tight or sagging.

Leg line

The trouser leg should fall in a clean, straight line from hip to shoe, with no excess fabric bunching and no pulling across the thighs. Many men prefer a slight taper toward the ankle, which a tailor can add.

The break

The break is the fold created where the trouser hem meets the shoe.

Break	What it looks like	Effect
No break	Hem just touches or sits above the shoe	Clean, modern, slim
Slight break	A small fold at the front	Versatile, most popular
Medium break	A clear single fold	Traditional
Full break	A deep fold, fabric resting heavily on the shoe	Very traditional; can look sloppy on slim cuts

Bring the shoes you will wear with the suit when it is being hemmed, since heel height changes the break.

What a tailor can fix

Usually straightforward and affordable:

Shortening or lengthening sleeves (within the available fabric).
Taking in or letting out the jacket waist.
Hemming trousers and adding or removing cuffs.
Taking in or letting out the trouser waist and seat (within limits).
Tapering trouser legs.

Difficult, expensive or impossible:

Changing shoulder width.
Significantly shortening a jacket.
Fixing a collar that does not sit well (sometimes possible, often costly).
Enlarging a jacket that is too small across the chest.

The rule: buy for the shoulders and chest, tailor the rest.

Off-the-rack, made-to-measure or bespoke?

Off-the-rack suits come in standard sizes. With alterations, they suit many men well and cost the least.
Made-to-measure suits adjust an existing pattern to your measurements, which helps if you are between sizes or have different-sized jacket and trouser needs. Many US retailers and online brands offer it.
Bespoke suits are built from a new pattern made for you, with multiple fittings. They offer the most precise fit and the most choice, at the highest cost and longest wait.

For most men, a well-chosen off-the-rack or made-to-measure suit plus a good tailor is the best value.

Do not forget the shirt

A suit is only as sharp as the shirt underneath it. The shirt collar should close comfortably with room for one finger at the neck, and the collar points should sit under the jacket lapels rather than flaring out. The body should be slim enough not to billow above the trouser waistband, and the sleeves long enough to reach the base of the thumb so that the cuff shows below the jacket. If shirts in your size are always too full, a slim or tailored fit, or a simple taper by a tailor, solves the problem.

Finding a good tailor

Ask well-dressed friends or a menswear store for recommendations. A good tailor will pin the garment while you wear it, ask how you like the fit, and explain what is and is not possible. Start with a simple job, such as hemming trousers, before trusting them with bigger alterations.

Final check

Before you leave the fitting, sit down, reach forward, lift your arms and walk around. A well-fitted suit should look sharp standing still and feel comfortable in motion. Get the shoulders right, the sleeves and trousers to the correct length, and the waist shaped to your body, and almost any suit will look as if it was made for you.

How a Suit Should Fit: A Head-to-Toe Checklist for Men