Suit Vents: Single, Double or None, and What Each One Does

A vent is the opening at the bottom of a jacket's back. It is a small thing to look at and a large thing to live in, because it decides what the jacket does the moment you stop standing still.

Most men never choose one. A jacket off the peg arrives with whatever vent the maker favours. In a bespoke house it is a decision like any other, taken at the consultation and cut into the pattern.

What a vent is actually for

A jacket is cut to sit closed and quiet across the seat while you are upright. Sitting down, reaching across a table, or sliding a hand into a trouser pocket all ask the back to be wider than it was cut. With nowhere to go, the cloth finds room by riding up over the seat, creasing across the hips, or pulling the front button out of line.

A vent gives the movement somewhere to go. It is a seam left open from the hem upwards, commonly eight to ten inches, so the skirt can part rather than strain. Cut well, it lies shut when you stand and opens only when asked.

Ventless

A ventless jacket has a closed back. Nothing interrupts the cloth from collar to hem, which makes it the cleanest of the three to look at and the least forgiving to wear. Sitting down it has no escape route, so it either rides up or presses against the seat and shows it. A ventless cut wants a wearer who stands more than he sits.

This is where the dinner jacket comes from. Black tie grew out of evening dress, worn standing, dancing and at table in clothes cut close to the body, and the ventless back suited that life. The convention survived, which is why a great many dinner jackets are still made without a vent, and why a ventless back is an early question on any custom tuxedo Los Angeles commission.

Single centre vent

A single vent is one opening up the middle of the back. It is the most common vent in the world, largely because it is the quickest to make, and because American tailoring settled on it early and never moved.

It works. When you sit, the vent parts and the jacket stays down. The difficulty is what it does with a hand in a pocket, or standing with your weight on one leg, which is how most men stand. Because there is one opening and it sits dead centre, any sideways movement pulls it open and the vent gapes, showing a slice of trouser seat. That is not a fault in the making but what a single central opening does on a body that is never quite symmetrical. It remains a sound choice on a shorter or more casual jacket, where a little movement in the skirt is part of the character.

Double side vents

Double vents are two openings, one over each hip, set in from the side seams. This is the European convention. English and Italian houses have used side vents for generations, and as a European house we cut them as our default.

Side vents behave better in the three situations that matter. Sitting down, both vents part and the jacket settles rather than climbing. A hand in a trouser pocket lifts one panel of the skirt and leaves the other where it was, so the back still covers the seat. Standing with your weight on one leg, the two panels shift independently and the centre of the back stays unbroken.

They also give a tailor more to work with. The two skirt panels can be shaped over the seat, so a jacket can be cut closer through the waist without the back misbehaving. That is more hand work, which is part of why side vents stayed with the houses that make by hand. Every garment we make is made by hand in our atelier in Southern Brittany, France.

Length, seat and posture

Jacket length comes first. A vent should finish just above the fullest part of the seat, which on a well proportioned jacket is around the level of your wrist bone when your arms hang. Shorten the jacket and the vent shortens with it.

The seat comes next. A fuller seat asks more of a jacket's back, and asks it in one particular place. Side vents handle that better, because the shaping can go where it is needed rather than meeting a centre seam head on.

Posture decides the rest. A man who stands with one shoulder low, or with his weight habitually on one side, will show a single vent gaping and side vents not at all. We look at this from behind you at the consultation, where the checks in how a suit should fit are also made.

What the house recommends

Double side vents on a suit or a sports jacket. Ventless on a dinner jacket unless you tell us otherwise. A single vent when you ask for one, and we will cut it properly rather than talk you out of it.

The choice is made at the free one-hour consultation, because it is cut into the pattern rather than decided after the jacket exists. A vent can be shortened later, but turning a single vent into side vents means re-cutting the back panels, which is new making rather than alteration. It sits with the other construction decisions: full canvas, half canvas or fused, the lapel, and whether the front is double-breasted or single-breasted, which bears on the vent because a double-breasted jacket nearly always wants side vents.

Around thirty measurements and three photographs are taken at that meeting, and the vent is settled there. To start, you can book a fitting, or see what a commission involves on our bespoke tailor Los Angeles page.

Questions we are often asked

What is a vent on a suit jacket?

An opening at the bottom of the jacket's back, usually eight to ten inches deep, so the skirt can part when you sit or move instead of riding up.

Are single or double vents better?

Double side vents behave better in almost every situation, and they let a jacket be cut closer through the waist. A single vent is sound on shorter, more casual jackets.

Should a dinner jacket have a vent?

Traditionally no. Evening dress was cut ventless and most dinner jackets still are, which gives the cleanest line down the back. We will cut vents into one if you prefer them.

Why does my jacket gape open at the back when I stand?

If it has a single centre vent, that is what a central opening does when your weight is not evenly placed. It is not usually a fault. Side vents on the next one will solve it.

Can a tailor add or change a vent?

A vent can be shortened, and a single vent can sometimes be closed if the jacket has the room. Converting one into side vents means re-cutting the back panels, which is new making rather than alteration.

Does a double-breasted jacket need double vents?

Nearly always. Its longer, closer skirt overlaps at the front, and a single centre vent tends to show that closeness at the back. Side vents keep it in order.

Which vent does MR JAMES recommend?

Double side vents on suits and sports jackets, ventless on dinner jackets, and a single vent when a client asks. Every garment we make is full canvas and fully bespoke, so the vent is cut to your pattern. See our custom suits Los Angeles page, or book a fitting in Playa del Rey.