Which Blazer for Which Room? Structure, Stance, and the Bust

Tuesday, 9 in the morning, a boardroom with a glass wall. She stands to present, buttons the jacket, and reaches for the clicker. If the shoulder is right, nobody notices the jacket. If it is wrong, 11 people notice it for 40 minutes and remember nothing she said.

A blazer passes or fails at 2 places, the shoulder and the chest, and nothing a tailor can do afterward will rescue a jacket that failed there. The charts show you 9 blazer shapes and tell you which fruit you are. The fitting room asks 4 questions first, then chooses the shape for the room you are walking into: the boardroom, the interview, the pitch, the client dinner, the wedding. This guide does it in that order, with every blazer Luna cuts photographed on a real woman.

If you have a full bust, read the section on the stance twice. It is the part the charts never print, and it is the difference between a jacket that looks like $600 and one that looks like it pulls.

Shop the pieces in this story: Blazers, and Business Outfits. Complete size runs are listed first.

“Clean, sharp, and beautifully tailored. This blazer feels intentional and confident, not trendy.”

The 4 tests, in the order a fitter runs them

1. The shoulder seam. The seam where the sleeve joins must sit at the end of your shoulder bone. Run a finger out from the neck until the bone ends; that is the spot. A seam down the arm makes a dropped, tired shoulder; a seam toward the neck pulls the lapel off the chest. Shoulder width is the one measurement no tailor can change without taking the jacket apart, so if this fails, put the blazer back.

2. The flat hand. Button the jacket. Slide a flat hand between your breastbone and the lapels. If it does not fit, the chest is too tight and the button will pull an X across the front. If a fist fits with room to spare, the jacket is too big. When the front lies flat with the hand inside, the chest is right.

3. The sleeve. A blazer sleeve ends at the wrist bone, or between the wrist bone and the base of the thumb, and shows 1/4 to 1/2 inch of shirt cuff or bare wrist. Sleeves are the safest alteration there is; expect to shorten them on almost any jacket bought off a rail, and think nothing of it.

4. The hem. A classic blazer ends between the hip bone and the top of the thigh, and for a formal room it covers the seat. A cropped blazer ends at the high hip and must not cut across the widest point of the belly or the hip. A long line blazer ends mid thigh on purpose, over a wide leg. Then move: hug yourself, reach for a laptop, cross your arms. Nothing should pull across the back.

The stance, and the bust

The stance is where the main button sits, and it decides what the jacket does to your torso. On a 2 button blazer the top button sits just under the bust and the lower near the navel; on a 1 button blazer the button sits at the natural waist. The rule is that the main button lands at your narrowest point, or a fraction below it, and never across the fullest point of the bust. A stance that is too high shortens the torso; too low and the front droops.

For a full bust: buy for the bust and let the tailor take in the waist, never the other way around. Choose a single breasted jacket with fewer buttons and a lapel that runs long, so the V opens the chest. A collarless blazer, which has no lapel to turn across the bust line, is often the cleanest answer of all. Leave the double breasted jacket, which adds a second layer of cloth exactly where you have volume, to a woman with a straighter line.

The blazers we cut, and the room each one is for

The 3 button tailored blazer

The default. A notched lapel, 3 buttons, flap pockets, a hem that covers the seat. It reads as the boardroom, the interview in finance or law, the client meeting where you would rather be underestimated for a minute and then not. It suits every bust size when the stance is right, and every height when the hem is.

The Barbara is that blazer in black, with a red trim at the pockets that only the person beside you will notice. Wear it buttoned over a plain shell for the boardroom and open over a silk blouse for dinner, with the Teodora pants or the Jody pencil skirt.

The single button with a notched lapel

1 button at the natural waist and a long lapel make the longest V in tailoring, and so this is the shape for a full bust and for a woman who wants the jacket to give her a waist. It is the pitch, the wedding guest, the lunch that turns into an evening.

The Agatha in ivory has the single button, flap pockets, and pearl detail, photographed over the ivory wide leg pants it was cut to match. As a suit it is the spring wedding and the mother of the bride at a garden ceremony; on its own over navy it is the pitch.

The peak lapel with 4 buttons

A peak lapel points upward and outward at the shoulder, which broadens a narrow shoulder and sharpens every line beneath it. With 4 covered buttons the front reads formal and precise. This is the jacket for a keynote, a panel, and a camera, because the lapel frames the face on screen and the color does the rest.

The Alexa in red, with long sleeves, is the color a room remembers; the same cut comes in navy with a 3/4 sleeve for the woman who wants the shape without the volume, and in white for the summer conference. 1 bold jacket, everything else quiet.

The fitted jacquard with a clasp

A jacquard is a pattern woven into the cloth rather than printed on it, and on a fitted jacket it gives the surface a low sheen that reads as evening without a sequin in sight. A clasp instead of a button keeps the front clean. It is the client dinner, the holiday party, the theater, and the blazer that turns a black dress into an outfit.

The Lucy in midnight blue jacquard is fitted through the waist with a notched lapel and a single clasp. Over the Lucy sheath it is a suit for a December board dinner; over wide leg pants it is the tuxedo alternative.

The collarless cropped blazer

No lapel, a hem at the high hip, a clean round neck. Without a lapel there is nothing to turn across a full bust, and without length there is nothing to shorten a petite leg. It is the blazer for a dress, because it ends where the dress waist begins and lets the skirt do what it was cut to do. It is the wedding guest, the christening, the cocktail hour, and the creative office.

The Lola in white closes with hooks, has a 3/4 sleeve, and is cropped to the high hip; over a black pencil skirt it is the contrast that reads as summer tailoring. The Frida is the black version with a zip, the one for a woman who wants the shape with no buttons at all. The Rhea does the collarless crop in turquoise and black tweed with a pearl trim, over a pleated skirt for a mother of the groom in spring.

The cropped blazer with a shawl collar

A soft shawl collar with piping and a 3/4 sleeve, cropped to the waist. Cropped means the jacket ends where high waisted pants begin, which puts the break at 1/3 and gives the legs 2/3; this is the proportion for a petite woman and for anyone with a long torso and shorter legs. The 3/4 sleeve shows the wrist and lightens the arm.

The Rina is a dark navy cropped blazer with a shawl collar edged in white piping and a 3/4 sleeve, the jacket over the Agatha wide leg pants that makes a 5 foot 3 woman look 5 foot 6.

The double breasted blazer

2 rows of buttons and peak lapels add width across the chest and a formality nothing else supplies. It suits a straight figure that wants presence and a pear that wants a heavier top line, and it should be worn buttoned, as a tuxedo is. A full bust or a short torso should choose the single button instead.

The Natasha in sand is the double breasted blazer with peak lapels, photographed as a suit with the matching wide leg trousers, the sand suit for a spring board meeting or a courthouse wedding.

The lace blazer

A blazer cut in lace is an evening jacket that behaves like tailoring: a collar, buttons, a hem at the hip, and a surface that lets the dress beneath show through. It is the layer over a sleeveless dress for a woman who wants her arms covered at a wedding or a gala without a shawl that slides.

The Jody lace blazer in black goes over the Jody lace cocktail dress or any plain sheath; it also comes in ivory with a wide collar and in bordeaux.

The houndstooth blazer

Texture adds volume, so a houndstooth jacket suits a straight or a pear figure and a room where a little pattern reads as creative confidence: an agency, a university, a client lunch. The Elena in gray houndstooth has a single button and pairs with the matching trousers for a suit or with black for a jacket.

How to wear it: dress, wide leg, knit, evening

With a dress. The blazer hem should sit near the dress waist or at the upper hip, never at mid thigh, where it cuts the dress at a random point. A cropped or collarless blazer over a midi dress at the waist; a tailored single breasted blazer over a knee length sheath for the boardroom; a jacquard or lace blazer over a plain column for dinner.

With wide leg pants. Volume below wants structure above. A single breasted blazer that covers the seat makes a column with a full length wide leg; a cropped blazer over a high rise wide leg defines the waist and lengthens the leg. Button the jacket, or wear it open over a tucked top, and never over an untucked tunic.

Over a knit. A fine gauge knit under a structured blazer modernizes it without losing polish; a thicker knit wants a softer, unstructured jacket. Whatever the knit, you must still be able to hug yourself.

As evening. A midnight jacquard or a black blazer over wide leg pants and a silk shell is the tuxedo; a lace or pearl blazer over a slip or a sheath is the cocktail hour. The fit rules do not relax after dark; the shoulder, the sleeve, and the stance still decide whether it looks expensive.

Which blazer for which room

Height and shape, briefly

Petite, 5 foot 4 and under: hem at the high to mid hip, or cropped at the waist over high rise pants; a starting range of 40 to 44 cm from the shoulder seam to the main button usually lands near the natural waist, but torsos vary, so trust the mirror. Tall, 5 foot 8 and over: a hem that fully covers the seat balances a wide leg and reads intentional rather than cropped. A full midsection: the button at your true narrowest point, a hem below the fullest part of the belly, a single button, and an open front over a column of 1 color. Full hips: a light shoulder and a hem at mid hip, not at the widest lower hip. Broad shoulders: no padding, a V from the lapel, the emphasis moved to the waist.

The blazer in inches

The shoulder. The seam sits on the bone, and 1/4 inch past it is the most a blazer may go without reading as borrowed. A seam 1/2 inch inside the bone pulls the sleeve up the arm and puts a diagonal line from the neck to the armpit; that jacket is a size small in the shoulder and no tailor will change it.

The chest. Button the jacket and slide a flat hand between the breastbone and the lapels: it should fit without pushing the lapels apart. An X of pull lines at the button means 1 of 2 things. If the X starts at the bust, the size is wrong; if it starts at the waist, the side seams can be let out 1/2 inch each for $35 to $70.

The sleeve. Ends at the wrist bone, or up to 1/2 inch below it, showing 1/4 to 1/2 inch of blouse. Shortening costs $25 to $30 for a plain cuff and $40 to $60 with working buttons, because the buttons move; ask whether the buttons work before you buy, and if they do, buy the sleeve closer to right.

The hem. Between the hip bone and the top of the thigh, which on most women is 22 to 24 inches from the shoulder seam for a classic blazer and 18 to 20 for a cropped one; a longline sits 2 to 3 inches lower and covers the seat. A hem can be raised 1 inch on a straight hem for $30 to $50 and not at all on a curved or vented one. The hem that covers a full midsection ends 2 inches below the fullest part of the belly, and not a fraction lower, or it reads as hiding.

The stance. The main button on the crease of the waist or 1/2 inch below it. On a 3 button jacket only the middle button closes; on a 2 button the top; on a single button, the 1. A double breasted closes fully or not at all.

Ease over a blouse. A blazer worn over a fine blouse needs 2 to 3 inches of ease at the bust; over a knit, 4. Buy the jacket for what you will wear beneath it 4 days in 5, and if that is a knit, buy the softer jacket.

The lapel and the face. A notched lapel 2.5 to 3 inches wide is the neutral. A peak lapel adds a diagonal that lengthens a round face and squares a soft jaw; a shawl collar rounds an angular one; a collarless blazer draws no line and lets the neckline beneath decide. A lapel wider than 3.5 inches on a frame under 5 foot 4 swallows the chest.

The questions women ask before they invest

How do I fit a blazer with a large bust and narrow shoulders? Buy for the shoulder, choose a single button with a long lapel or a collarless cut so nothing turns across the bust, and have the waist taken in. A jacket that fits the bust and hangs off the shoulders can only be rebuilt; a jacket that fits the shoulders and is let out 1/2 inch at the side can be worn on Monday. The Agatha single button and the Lola collarless are the Luna answers.

Too small, or just fitted? Fitted: a flat hand behind the lapels, no X at the button, and you can hug yourself. Too small: any 1 of those fails. A jacket that is fitted is comfortable seated; a jacket that is small is not.

Can a tailor take in just the waist to make a blazer more feminine? Yes, 1/2 to 1 inch at each side seam and the back seam, for $35 to $70. That is the most rewarding alteration on a jacket that was bought for the shoulder.

Are cropped blazers right after 40? Yes, over a high rise and over a dress, where the crop puts the break at the waist and lengthens the leg. The Rina, the Lola, and the Frida are cut for it. A crop over a low rise or an untucked top, no, at any age.

Do longline blazers make you look slimmer or boxy? Slimmer when worn open over a column of 1 color with the hem covering the seat and the shoulders clean; boxy when buttoned on a frame under 5 foot 4 or over a wide leg that is also long. Petite, keep the hem at the hip.

Are shoulder pads necessary? A light pad of 1/4 inch squares a sloping shoulder and holds the line of the jacket; a 1/2 inch pad on a broad or square shoulder makes a room look at the jacket. A tailor can remove a pad for $20 to $40 if you prefer none.

Which lapel for a round face? A peak lapel or a long notched lapel; the diagonal lengthens. A shawl collar rounds it further.

Can a director wear an oversized blazer? A soft, slightly long blazer with the shoulder on the bone, yes; a jacket with the seam 2 inches down the arm reads as borrowed in any room, and in a boardroom as unserious. The line between oversized and ill fitting is the shoulder.

How long should a blazer be to cover my stomach without looking frumpy? 2 inches below the fullest part, a single button at the crease of the waist, and an open front over a column of 1 color so the eye reads the vertical and not the hem.

1 black blazer for work and for dinner? The Barbara: 3 buttons, notched lapel, hip length; buttoned over a blouse for the room, open over a silk shell and the Agatha wide leg for the dinner. If your bust is full, the Agatha single button in ivory or the Lucy jacquard with a clasp does the same.

Is a $600 blazer worth it if I wear it 3 days a week? 3 days a week for 40 working weeks is 120 wearings a year; over 5 years that is $1 a wearing. It is worth it if the shoulder fits, and only then.

Signs of good tailoring in a woman's jacket? A shoulder seam that lies flat with no ripple, a lapel that rolls rather than folds, a pattern that matches at the seams, a lining that does not pull at the hem, sleeve buttons that sit in a line, and a hem that hangs level when buttoned. If the jacket does all 6 in a photograph, it will do them on you.

Frequently asked questions

How should a blazer fit a woman? The shoulder seam sits at the end of the shoulder bone, a flat hand fits between the breastbone and the closed lapels, the sleeve ends at the wrist bone with 1/4 inch of cuff showing, and the hem sits between the hip bone and the top of the thigh. You can hug yourself and reach forward without pulling.

Which blazer is best for a large bust? A single breasted jacket with 1 or 2 buttons and a long lapel, or a collarless blazer, bought to fit the bust and taken in at the waist. The main button sits below the fullest point of the bust. Avoid double breasted jackets, which add cloth where you have volume.

Single breasted or double breasted? Single breasted is the default for the boardroom, the interview, and any full bust. Double breasted adds width and formality across the chest, suits a straight or pear figure, and should be worn buttoned.

How do I wear a blazer with a dress? Choose a hem that sits at the dress waist or upper hip. A cropped or collarless blazer over a midi lets the skirt move; a tailored blazer over a knee length sheath is the office; a jacquard or lace blazer over a plain dress is the evening.

Which blazer for a petite woman? A cropped blazer that ends at the waist over high rise pants, or a classic blazer with the hem at the high hip. A hem at mid thigh shortens the leg. The 3/4 sleeve helps too; it shows the wrist.

Can a tailor fix the shoulders? Not without taking the jacket apart. Buy the shoulder that fits and alter the sleeve and the waist, which are the safest alterations. If the shoulder or the chest fails, no tailor can make it look like a $600 jacket.

The Fitting Room at Home

Order the 2 sizes that bracket your shoulder. Run the 6 tests in your own mirror, in the shoes and the blazer you will wear. Keep the one that passes and send the other back within 30 days, self serve, no questions. If you would rather be told, send your 3 numbers, shoulder, bust, and hip, and the day it is for, to connect@lunafashionhouse.com; a person who knows the cut replies within 1 business day with the size and the piece.

Run the 4 tests, put the button at your narrowest point, and then choose the room. The Barbara for the boardroom, the Agatha for the pitch and the wedding, the Alexa for the stage, the Lucy for dinner, the Lola over a dress. See them all in Blazers and in Business Outfits, complete size runs first, with 30 days to run the tests at home.