A blazer is the one garment that will change more outfits than any other. It is also the one most often bought in the wrong size.
A blazer does something no other garment does. It takes a dress you already own, or a pair of trousers and a plain top, and makes the whole thing look deliberate. It is the single most efficient purchase in a wardrobe.
It is also the garment where fit matters most and where the store mirror is least reliable. The notes below are the ones worth having before you spend anything.
Start With the Shoulder
Every other part of a blazer can be altered. The shoulder cannot, or at least not without more money and more skill than the jacket is usually worth.
The shoulder seam should sit at the point where your shoulder ends and your arm begins. If it falls onto the upper arm, the jacket will collapse and the sleeve will hang badly no matter what the rest of it does. If it sits inside your natural shoulder, the jacket will pull across the back every time you reach forward.
Test it by putting both arms straight out in front of you. Some pull across the upper back is normal. Fabric straining at the seam is not.
Then the Button Stance
The button stance is where the fastening sits relative to your waist, and it changes the character of the jacket completely.
A higher stance, closer to the natural waist, creates a defined shape and reads more formal. It suits a shorter body and works well over a dress.
A lower stance creates a longer lapel line and a more relaxed jacket. It layers more easily over knitwear and reads as contemporary rather than corporate.
Neither is better. But a jacket whose stance sits at the widest part of your torso will always be a fight, and that is worth checking before anything else.
The Four Cuts Worth Knowing
The Single Breasted, Single Button
The most versatile and the least demanding. One button at the waist, a clean lapel, nothing to manage. If you are buying one blazer, buy this.
The Double Breasted
Two columns of buttons and a wider overlap. Considerably more formal and more structured, and it wants to be worn fastened. Superb over trousers and a fine knit, less easy over a full skirt.
The Longline
Cut to mid thigh or below. It reads as a coat as much as a jacket and works particularly well over a dress, because the length carries the line rather than cutting it.
The Peplum or Shaped
A flared panel below the waist seam. It gives definition without a belt and sits well over straight skirts and tailored trousers. It is the least flexible of the four but the most distinctive.
Every part of a blazer can be altered except the shoulder. Buy for the shoulder and adjust the rest.
Length, and How to Judge It
A classic blazer ends somewhere around the top of the hip or just below. That length works over almost everything, which is why it has survived.
The useful test is what the jacket does to the proportion of your leg. A hem that stops at the widest point of the hip shortens the leg line. A hem an inch or two below it does not. This is often the difference between a jacket that works and one that hangs in the wardrobe, and it has nothing to do with size.
For a longline, ignore the hip entirely and check mid thigh. It wants to end well clear of the knee.
What to Wear It With
Over a midi dress, a blazer turns an occasion piece into something you can wear to work. This is the combination that earns the purchase.
With straight or wide leg trousers and a plain top, it becomes the simplest smart outfit available, and the fewer competing details the better.
Over a knit, choose a jacket with a lower button stance and a little more room. A blazer cut close to the body will not accommodate a sweater, and forcing it produces a strained line across the back.
Fabric and the Practical Question
A jacket with some texture in the cloth, a tweed or a woven check, hides creasing and wear far better than a flat weave and will look considered for longer. A smooth cloth reads sharper and more formal but shows everything.
Check the lining and the vents. A fully lined jacket hangs better and lasts longer. A single or double vent at the back lets the jacket sit properly when you are seated, which a vent-less jacket will not.
Fabric Through the Year
A blazer is a year-round garment only if you own more than one, and the fabric is what separates them.
A wool or wool-blend blazer is the fall and winter workhorse. It holds a shoulder, it recovers from creasing overnight, and it takes a shirt or a knit underneath without straining.
A linen or linen-blend blazer is the summer answer, and it will crease. That is what linen does, and a linen jacket that has been sat in looks lived in rather than untidy, which is a distinction worth accepting rather than fighting.
A crepe or a fluid woven blazer is the evening one. It has no structure to speak of, hangs rather than holds, and works over a dress where a stiff jacket would look like office wear.
A jacket with some texture in the cloth, a tweed or a woven check, is the most forgiving of all, because the surface disguises both creasing and ordinary wear.
The Alterations Worth Paying For
A blazer bought off the rack rarely fits in more than two places at once, and the two alterations that transform one are both inexpensive.
The sleeve length. A blazer sleeve should end at the wrist bone, or a little above it if you want a cuff to show. Shortening a sleeve from the cuff end is straightforward on most jackets and it is the single change that makes a blazer look tailored rather than borrowed.
The waist suppression. Taking in the back seam by an inch or two changes a boxy jacket into a shaped one. Any alterations shop can do it and it costs very little.
What is not worth altering: the shoulder. A blazer whose shoulder seam does not sit where your shoulder ends is the wrong jacket, and moving it is expensive and rarely successful. Check the shoulder first and everything else second.
Living With One
Hang it on a broad wooden hanger, not a wire one, and give it a day between wears so the cloth recovers. Brush a wool blazer rather than washing it. Dry clean it once or twice a year at most, since the process is harder on tailoring than most people realize, and spot clean between times.
Blazers Worth Building Around
Common Questions
What Is a Blazer for Woman?
A blazer is a tailored jacket with structured shoulders, lapels and a front fastening, cut to be worn over other clothing rather than as outerwear. It sits between a suit jacket and a casual jacket, and it is designed to be worn with pieces it does not match.
Buy for the shoulder, check what the hem does to your leg line, and choose the cut that suits what you already wear rather than the one that looks best on the rack. A blazer bought that way will be in use for years.