Suit Jacket Vents: Single, Double, and Ventless Explained

A vent is the slit at the back of a suit jacket. It exists so the jacket can move with you when you sit, walk, or put your hands in your pockets. There are 3 options: a single vent in the center, a double vent with a slit at each side, or no vent at all.

Which one you choose changes how the jacket hangs, how it behaves when you sit down, and how forgiving it is of your build.

What Is a Vent on a Suit Jacket?

A vent is a vertical opening cut into the bottom of the jacket at the back, running up from the hem. Most are 8 to 10 inches long.

The purpose is movement. A jacket with no opening at the back has to stretch across the seat every time you sit or reach, and the fabric has nowhere to go. A vent gives it somewhere to go.

Vents come from riding. Coats were slit at the back so they would fall either side of a saddle instead of bunching underneath the rider. Side vents served a second purpose, giving access to a sword or a pocket without lifting the whole coat. The military and equestrian origin is why vents are standard on tailored jackets and absent on most formal evening wear.

What is the slit at the back of a suit jacket called?

It is called a vent. If there is one slit in the middle, it is a single or center vent. If there are 2 slits, one at each side, they are side vents and the jacket is described as double vented. A jacket with no slit is ventless.

You will also hear the vent called the back slit, the back flap, or the split. They all refer to the same thing.

The 3 Types of Suit Jacket Vent

Single vent

One slit up the center back. This is the most common vent on suits sold in the United States, largely because it is the cheapest of the 3 to construct.

It works. It is not the best option for most men. When you sit, or when you put your hands in your trouser pockets, a single vent pulls open and exposes the seat of your trousers. The wider your hips and seat, the more pronounced that is.

Choose a single vent if you want a conventional American cut, or if the jacket is a casual one you will not sit in for long stretches.

Double vent

2 slits, one above each hip. This is the British approach and it is the better-engineered option.

The advantage is what happens when you move. Each side vent opens independently, so when you put your hands in your pockets the fabric parts at the sides rather than flaring open at the center. When you sit, the panels overlap rather than gape. From behind, a double vented jacket keeps its shape in situations where a single vent does not.

It costs more to make, because it requires more precise cutting and 2 finished openings rather than 1. On our suit jackets the vent style is set when the jacket is cut to your measurements.

Ventless

No slit at all. The back is a single unbroken panel.

The argument for it is the line. From behind, a ventless jacket is the cleanest of the 3, with no opening to break the fabric. This is why it remains standard on formal evening wear.

The argument against it is everything else. With nowhere for the fabric to go, a ventless jacket pulls across the seat when you sit and creases badly. It suits a slim build and a man who spends most of the evening standing. It is a poor choice for a suit you will wear at a desk.

Which Vent Style Suits Your Body Type

Vent choice is one of the few tailoring decisions where build should decide for you.

• Wider seat or hips: double vent. The side slits absorb the width instead of flaring open at the center. This is the single most useful thing to know on this page.
• Slim build: any of the 3 work. Ventless is viable here in a way it is not for other builds.
• Tall: double vent, and ask for slightly longer vents. Standard vent length can look short on a longer jacket.
• You sit for most of the day: double vent. A single vent spends the whole day pulled open.
• You keep your hands in your pockets: double vent, for the same reason.

If you are unsure of your build, our guide to male body types covers how to identify yours before you order.

The short version: unless you specifically want the clean back of a ventless jacket or the conventional look of a single vent, a double vent is the safer default for most men.

How to Check the Vent When You Try a Jacket On

The vent tells you things about the fit that the front of the jacket hides. 4 checks, in the order worth doing them:

1. Stand still, arms down. The vent should lie closed and flat. If it hangs open while you are standing relaxed, the jacket is too tight across the seat or the hips. That is a sizing problem, and changing the vent style will not solve it.

2. Put your hands in your trouser pockets. A single vent will pull open; that is normal and expected. What you are checking is how far. If the vent flares wide enough to show the whole seat of your trousers, size up or move to a double vent.

3. Sit down. On a double vent the 2 panels should overlap or part cleanly. On a ventless jacket, look for hard diagonal creases radiating from the seat. Some creasing is unavoidable; deep pulling means the jacket is too tight to sit in comfortably.

4. Look at the hem. The vent should end level and closed, with both edges meeting. If one side hangs lower than the other, the jacket is either badly pressed or badly balanced, and a tailor should see it before you buy.

Do these 4 in front of a mirror you can turn away from, or with someone else looking. The back of a jacket is the part you will never see and everyone else will.

Tuxedo Vents

Tuxedos are traditionally ventless.

The reasoning is that formal evening wear prioritizes line over practicality. A dinner jacket is meant to read as a clean silhouette, and a vent interrupts that. Most classic tuxedos, and almost all older ones, have no vent.

Modern tuxedos are increasingly cut with side vents, and that is now widely accepted. A single vent on a tuxedo is the least traditional of the 3 and the one most likely to be noticed by someone who cares.

The practical trade-off matters at a black tie event, where you will be seated for a dinner and possibly for speeches. A ventless dinner jacket will crease across the seat over a long evening. If that bothers you more than tradition does, choose side vents. Our tuxedos are made to your measurements, so the vent is your decision rather than the stock jacket's.

Blazer and Sport Coat Vents

The same 3 options apply, but the convention differs.

British-cut blazers and sport coats are usually double vented. So are most tweed jackets, which inherit the equestrian and country heritage directly. A tweed jacket with side vents is the traditional configuration, not a modern preference.

Casual sport coats are more often single vented, particularly in American cuts. Ventless is rare outside formal wear and looks out of place on a casual jacket.

One practical note: because a blazer is worn more often without a matching trouser, the back of the jacket is more visible against contrasting trousers. A double vent holds its shape better in that situation.

Suit Jacket Vents: Frequently Asked Questions

What is the X stitch on the back of a new jacket?

It is a basting stitch, and you need to cut it before wearing the jacket. New jackets ship with the vents stitched closed, usually with a loose X or a single line of thread, to keep the fabric flat during shipping and on the hanger. It is not part of the garment.

Cut it carefully with small scissors or a seam ripper, taking the thread and not the fabric. The same applies to pockets, which are often basted shut on a new jacket. Wearing a jacket with the vents still stitched is one of the most common and most visible mistakes with a new suit.

Should you remove the stitch on a new suit jacket vent?

Yes, always. The stitch is temporary. Leaving it in defeats the purpose of the vent, prevents the jacket from moving with you, and is noticeable from behind because the vent puckers where the thread holds it.

The exception is the brand label stitched to the outer sleeve on some jackets, which is also meant to be removed but is a separate thing.

Is a single or double vent better?

A double vent is better for most men. It handles sitting, movement and hands in pockets without gaping, and it is more forgiving of a wider seat. A single vent is the more conventional American look and costs less to make.

Choose a single vent if you want that traditional cut. Choose a double vent if you want the jacket to behave well in normal use.

Are ventless suit jackets out of style?

For business suits, largely yes. Ventless suiting had a period of popularity and is now uncommon outside formal wear and some Italian tailoring. It has not disappeared, and on a slim build with a well-cut jacket it still looks correct.

For tuxedos and dinner jackets, ventless is not out of style at all. It remains the traditional choice.

Do vents affect how a suit fits?

Vents do not change the measurements of the jacket, but they change how a given fit behaves in motion. A jacket that fits well standing still can look poor when you sit if the vent is wrong for your build.

A vent that pulls open while you are standing with your arms down is a sign the jacket is too tight across the seat or hips. That is a fit problem, not a vent problem, and no vent style will fix it.

How long should a suit jacket vent be?

Between 8 and 10 inches on a standard jacket, measured up from the hem. Longer jackets take longer vents. A vent that is too short restricts movement and defeats the purpose; a vent that runs too high up the back exposes more than intended when you sit.