How a Suit Should Fit: The Six Points

A suit is the one garment where almost everybody can tell something is wrong and almost nobody can say what. The jacket is not obviously too big. The trousers are not obviously too long. It just looks like a suit wearing a man rather than the other way round.

The useful thing about a suit is that the diagnosis is short. Six points decide it, and only two of them are decided at the till. The other four are a conversation with a tailor that costs a fraction of what the suit cost.

The short answer

Buy for the shoulder and the chest. Fix everything else afterwards.

If you remember one line from this guide, it is that the first two rows are the purchase and the last four are the appointment.

The shoulder is the whole decision

The shoulder is where a jacket is built, not just where it is measured.

Underneath the cloth of a jacket shoulder there is a sleeve head, sometimes a pad, and canvas that shapes the chest. Moving the shoulder means taking all of that apart and putting it back together, which is why a tailor who is willing to do it will quote you a number that makes buying a different jacket look sensible.

Yaroslav Shuraev / Pexels

What to look for, standing straight with your arms down:

• The seam ends where you end. Find the bony point where your shoulder stops being flat and starts sloping into your arm. The seam should land there.
• No divot below the seam. A dent or ripple just below the shoulder seam means the jacket’s shoulder is wider than yours and the fabric has nowhere to go.
• No pull across the back. Raise both arms halfway. If the whole jacket rides up with them, it is too tight across the upper back.

The chest is the same category for the same reason. Fasten the top button and look at the front. If the fabric pulls into an X radiating from the button, the chest is too small, and letting it out is either impossible or as expensive as the shoulder.

What a tailor moves, and roughly what it does

Everything below the shoulder is a conversation, and the conversation is cheap relative to the garment.

The jacket waist. The most common alteration and the one that changes the silhouette most. A jacket taken in at the waist stops being a rectangle and starts following a shape. Ask for it to be suppressed enough to show you have a waist and not so much that the vents flare open when you stand still.

Sleeve length. Standard, quick, and the difference between a jacket that looks bought for you and one that looks borrowed. The target is one to two centimetres of shirt cuff visible with your arms hanging.

Trouser waist and seat. Also routine, within about two inches in either direction. A waistband that needs a belt to stay up is a waistband that has not been altered.

Trouser length. The last thing done, because it depends on which shoes you wear it with. Bring the shoes.

Ketut Subiyanto / Pexels

Jacket length and the button point

Two measurements decide the proportions of a jacket, and neither one is negotiable after purchase in any cheap way.

The button point. On a single-breasted jacket the fastening button should sit at or a little below your natural waist, which is the narrowest part of your torso and usually somewhere around the navel. When it sits there, the jacket divides you into two roughly balanced halves and the lapels form a long clean line down to it. When it sits too high the jacket looks stubby; too low and the lapel line goes on so long the jacket reads as a coat.

You cannot move a button point. Moving the button moves the buttonhole, the lapel roll and the balance of the whole front. This is one to check in the mirror, from a distance, before you get attached to a jacket.

Overall length. The jacket should cover your seat. The old advice is to stand with your arms hanging and curl your fingers under the hem, and it is a reasonable first approximation that breaks on men with unusually long or short arms. The reliable version is the seat: turn side-on to a mirror and check that the hem covers it. A jacket that stops above the seat reads as too small no matter how well the shoulders fit.

Shortening a jacket is possible but limited, because the pockets and the vents were placed relative to the original hem. A centimetre or two is routine. More than that and the proportions of the pockets start to look wrong even if the length now looks right.

What “good cloth” actually means

Suit shopping is full of numbers that sound like quality and mostly describe something else.

Super numbers. Super 110s, 130s, 150s and upward describe the fineness of the wool fibre, not the quality of the finished cloth. Finer is softer and drapes better, and it is also more fragile and creases more readily. For a first suit that has to survive commuting and being sat in, a lower super number is usually the more practical choice, not the compromise.

Weight. Cloth weight, given in grams per metre, tells you more about how a suit will behave than the super number does. Lighter cloth wrinkles more and hangs less well; heavier cloth holds its shape and is warm. Something in the middle covers three seasons in most climates.

Lining and construction. A fully canvassed jacket has a layer of horsehair canvas floating between the cloth and the lining, which moulds to your chest over time. A fused jacket has that layer glued. Fused is cheaper, lighter and can bubble after years of dry cleaning. Half-canvassed sits between the two and is where most reasonable suits land.

None of this outranks fit. A fused suit that fits will look better than a fully canvassed one that does not, every single time, and the alterations budget beats the construction upgrade for anyone buying their first.

The rules that are conventions, not physics

A lot of suit advice is delivered as though it were structural. Most of it is inherited convention, and it is worth knowing which is which, because conventions change and structure does not.

Conventions. The bottom button stays undone. Brown shoes with navy, black with charcoal. No more than two centimetres of cuff. Trouser break. Tie length reaching the belt buckle. All of these are agreements rather than mechanics. Some have practical origins that have long since stopped mattering.

Structure. The shoulder seam, the chest, the seat of the trousers, and the point where the jacket’s button sits relative to your natural waist. These are not opinions. Get them wrong and the garment hangs wrong regardless of how well you follow the conventions.

The test to apply to any suit rule you are handed: ask what happens mechanically if you break it. If the answer is a description of fabric behaving badly, it is structural. If the answer is that people will think something, it is a convention, and conventions are worth following where they are cheap and worth ignoring where they are not.

The trouser question people get wrong

Trousers are where most otherwise-good suits fall over, and it is almost always length.

Jonathan Borba / Pexels

The break is the fold the fabric makes where the trouser meets the shoe. No break means the hem just kisses the top of the shoe. A slight break means one soft horizontal fold. A full break means the trouser sits on the shoe and folds clearly.

Anything from no break to a slight break reads as current. A full break reads as older and is not a mistake. What does read as a mistake is trousers that pool over the shoe in several folds, because that is not a break, it is length nobody altered.

Two checks worth doing in the fitting room:

• Sit down. If the waistband digs in or the seat pulls tight, the trousers fit you standing and not living.
• Pinch the thigh. You should be able to take two or three centimetres of fabric between your fingers. Less than that and they are painted on; much more and they are baggy.

What the research actually supports

Almost everything above is craft knowledge, which is to say it is inherited and mostly sensible and rarely tested. Two things about suits have actually been measured, and it is worth being precise about what each one shows.

The first is about how quickly other people respond to fit.

Note what this does and does not establish. It does not show that people can identify a tailored suit. It shows they respond differently to one within five seconds, without being able to say why, which is a stronger argument for the alteration bill than any amount of tailoring folklore.

The second is about the man wearing it, and here the evidence is weaker and worth reading with its limits attached.

So the honest summary is: there is a measured effect on other people’s snap judgements, and there is a smaller, shakier literature suggesting formal clothes change how the wearer thinks. Treat the first as a reason to pay a tailor and the second as interesting rather than settled.

The fitting room routine

Everything above collapses into about ninety seconds of checks, done in this order, because each one rules out the jackets that the next check would waste your time on.

1. Put the jacket on and do nothing. Arms down, standing straight. Look only at the shoulder seam and where it ends.
2. Fasten the top button. Look for an X of tension radiating from it. If it is there, the chest is too small and you are finished with this jacket.
3. Turn side-on. Check that the hem covers your seat and that the button sits around your natural waist.
4. Raise both arms halfway. If the jacket climbs with them, the back is too tight.
5. Look at the collar from behind, or ask someone. A gap between the jacket collar and your shirt collar means the jacket does not sit on your neck properly, and that is a structural problem rather than an alteration.
6. Only now look at the sleeves, the waist and the trousers. All of these are the tailor’s problem, so they are not reasons to reject a jacket that passed the first five checks.

The order matters because most people do this backwards. They notice the sleeves are long, reject the jacket, and buy one with correct sleeves and the wrong shoulders. The sleeves cost twenty minutes of a tailor’s time. The shoulders cost the price of the suit.

Buying a first suit

If this is your first, the decision is narrower than it looks.

Navy or charcoal, plain, single-breasted, two buttons, in a wool that is not shiny. That combination works for an interview, a wedding and a funeral, which covers essentially every reason a man in his twenties needs a suit. Save the pattern, the colour and the double-breasted cut for the second one, when you know you will use it.

Buy it when you have a date for wearing it. A suit bought speculatively sits in a cupboard until your body or the cut has moved on, which is the most common expensive mistake in a first wardrobe.

Then take it to a tailor the same week. The suit you buy is not the suit you wear, and the gap between them is a single appointment.

The mistakes worth avoiding

• Buying a size up because the chest feels tight. Check whether it is the chest or the shoulder. If it is the shoulder, no size fixes it. If it is the chest, you are in the right jacket and the wrong size.
• Judging length by the fingertip rule alone. It is a rough guide that fails on long or short arms. Look at whether the jacket covers your seat.
• Getting the trousers hemmed without the shoes. The hem is set by the shoe. A different heel height changes the break.
• Letting a shop assistant tug the back of the jacket flat. Everything looks like it fits when somebody is holding the fabric. Ask them to let go.
• Wearing a suit only when it is required. A suit you have never worn before an interview is a suit you will fidget with during it.
• Skipping the tailor because the suit was cheap. That is backwards. The cheaper the suit, the more of its final appearance is decided by the alterations.

Looking after it, so it survives

A suit is the most expensive thing in most first wardrobes and the one most often ruined by routine handling.

Hang it on a broad hanger, immediately. A jacket left over a chair overnight keeps the creases. The wide hanger supports the shoulder the way it was built to be supported; a thin wire one deforms it permanently over months.

Brush it rather than cleaning it. A clothes brush after each wear removes the dust that abrades fibres. Dry cleaning is a solvent process, it is hard on structured garments, and a suit worn a handful of times a year needs it very rarely.

Let it rest. Wool recovers its shape given a day. Wearing the same suit on consecutive days is what makes the knees and elbows keep their bend.

Deal with a stain properly, once. Blotting with water and no heat, and then a specialist if that fails. The one thing that permanently ruins suiting is rubbing at it.

Done consistently, this is the difference between a suit that lasts a decade and one that looks tired after two years, and none of it takes more than a minute at a time.

The bottom line

Buy for the shoulder and the chest, because those are the two things nobody can fix. Then spend a small fraction of what you paid on moving the waist, the sleeves and the hem.

That is the entire difference between a suit that wears you and a suit that fits, and it is a difference other people register in about five seconds without knowing what they are looking at.