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Most winter coats are bought in a hurry, in a warm store, over a T-shirt. The shoulders feel fine, the sleeves reach the wrist, and the price is right. Then January arrives, a sweater goes underneath, and the coat pulls across the back, rides up at the collar, and leaves two inches of wrist exposed every time you reach for a door handle.
The problem is that a coat is a layered garment being fitted like a shirt. Its measurements have to account for what you wear underneath, and its construction has less adjustment room than almost anything else in the wardrobe.
This guide works through the coat in the order a tailor would: shoulder, armhole, sleeve, body, hem, collar. It also covers how much ease to leave, and which fixes are worth paying for.
Start With the Layers You Actually Wear
Bring the sweater. Not a hope of a sweater, and not the thin one you wear in October, but the bulkiest knit that will realistically go under the coat. If you wear a suit to work, bring the jacket too. A coat fitted over a dress shirt will be a size too small by the time a blazer, a scarf, and a commute are involved.
The difference is measurable. A merino crew neck at 12 gauge adds roughly half an inch to the chest and a quarter inch to each sleeve. A chunky lambswool sweater can add an inch and a half. A suit jacket adds around three-quarters of an inch at the chest and more at the upper arm.
This is why the three-layer system is worth understanding before you shop. The coat is the outer layer, and it has to close over everything beneath it without compressing the insulation. If your winter wardrobe is already settled, the closet audit will tell you which two or three layers the coat actually has to accommodate.
The Shoulder Seam Sets the Size
The shoulder seam should sit at the outer point of your shoulder bone, known as the acromion, or no more than half an inch past it. This is the first thing to check and the last thing a tailor can fix cheaply. A shoulder that is too narrow pulls the sleeve upward and creates a diagonal crease from the collar to the armpit. A shoulder that is too wide collapses over the arm and makes the coat look borrowed.
Padding complicates the read. A structured overcoat may have a quarter inch of wadding that extends the line past your natural shoulder; that is intended. Judge the seam against the bone, not against the padding edge. For an unstructured coat, the seam should follow the bone closely.
Raglan sleeves change the test. There is no shoulder seam, so the fit is judged by the drape from collar to armpit. A raglan should lie flat across the collarbone without a fold, and the fabric should not pull when you raise an arm. Drop-shoulder coats are deliberately oversized; accept the extra width or choose a different cut, because the seam is not moving.
Armhole and Sleeve Width: Where Movement Comes From
A high armhole sits close under the armpit and gives better range of motion, because the sleeve pivots near the joint instead of dragging the whole coat upward. A low, roomy armhole feels comfortable when you stand still and restricts you the moment you reach overhead, which is exactly when a winter coat is doing real work.
Test it with the coat closed. Raise both arms to shoulder height, then overhead. The hem should not lift more than two or three inches, and the collar should not press against your throat. If the whole coat rides up like a cape, the armhole is too low or the chest is too tight.
Sleeve width needs enough room for a sweater and a shirt, usually one to two inches of ease around the upper arm. Too much and the sleeve swallows your hand; too little and the fabric bunches at the elbow. Make a fist and rotate your forearm; the sleeve should follow without twisting the body of the coat.
Sleeve Length: Wrist Bone, Watch, and Glove Gap
With arms at your sides, a coat sleeve should end roughly half an inch to an inch past the wrist bone, or at the base of the thumb. It should cover the cuff of a jacket underneath by a quarter to half an inch. Any longer and it interferes with gloves and makes the hands look small; any shorter and cold air runs straight up the sleeve.
Check the length with the arm bent, not just hanging. A sleeve that looks correct standing still can retreat two inches when you grip a steering wheel. Sit down, bend both elbows to 90 degrees, and see where the cuff lands.
Shortening is usually possible from the cuff, up to about an inch and a half. Beyond that, the pocket placement and the sleeve vent start to move. Working buttonholes make the job more expensive because the buttons have to be moved and the buttonholes resewn by hand, which is why a functioning cuff is a detail worth paying for only when the sleeve already fits.
Body Width: How Much Ease You Need
Coat sizing is built on ease, the difference between your body measurement and the garment measurement. For a winter coat over a shirt and a light sweater, look for three to four inches of ease at the chest. Over a suit or a heavy knit, five to six inches.
You can check this without a tape measure. Button the coat and slide a flat hand under the front panel at the chest. It should fit with a little pressure. Then sit down: the front should not gape open at the bottom button, and the back should not pull tight across the shoulder blades.
Measure a coat you already own, flat, from armpit to armpit, and double it. Compare that number with your chest measurement plus the ease above. This is more reliable than the tag, because a size 40 from one brand can measure 21 inches across while another measures 23. The down versus synthetic comparison is a useful reminder that warmth comes from loft and dead air, not from squeezing more layers into a tight shell.
Hem Length by Coat Type
Hem length is mostly a question of proportion, and the coat should end somewhere deliberate rather than at the widest part of your body. Measured from the base of the back collar to the hem, a practical range looks like this:
- Hip-length or peacoat: 30-32 inches, ending at the hip bone or just below.
- Car coat: 34-38 inches, mid-thigh.
- Overcoat or topcoat: 42-46 inches, just above or at the knee.
- Full-length: 47-50 inches, below the knee, for formal or severe cold.
Height shifts these numbers by an inch or two, and so does leg length. The visual rule is simpler: the hem should not cut you in half at the widest point of the thigh, and it should cover the jacket underneath when you wear one. A coat that stops above a suit jacket hem looks like it shrank.
Button stance matters too. A double-breasted coat with a low stance lengthens the torso; a high stance shortens it. The peacoat button spacing guide explains how the row count and spacing change the silhouette before you ever get to the hem.
Collar, Lapels, and Room for a Scarf
A coat collar should stand about an inch and a quarter to an inch and three-quarters at the back of the neck, close enough to block wind but not so close that it strangles a shirt collar. With the coat buttoned, turn the collar up and check that it meets your jaw without pushing your chin forward.
Scarf room is part of the fit. A thick wool scarf needs roughly half an inch of clearance at the neck when wrapped once. If the collar already sits tight against your throat, the scarf will force the collar outward and leave a gap at the back.
Lapel width on an overcoat usually runs three to three and three-quarter inches, a little wider than a suit lapel because the coat is a larger garment. A notch lapel is the versatile choice; a peak lapel reads more formal; a stand collar or funnel neck is the cleanest option for very cold weather and eliminates the scarf gap entirely.
Alterations Worth Paying For
A coat has more usable seam allowance than a suit jacket in some places and much less in others. The practical list looks like this.
- Sleeve shortening: $35-65, or $70-120 with working buttonholes. Worth it when the shoulder and chest already fit.
- Waist suppression: $40-80. Worth it on a coat that is correct at the shoulder but boxy through the middle.
- Hem shortening: $30-60. Worth it, and usually straightforward unless the coat is lined with a complex vent.
- Lining replacement: $60-100. Worth it on a good coat with a torn lining, since the shell can outlast two linings.
- Shoulder narrowing: $150-300. Skip it. The result rarely matches the original line, and the cost approaches a better-fitting coat.
Before committing, read the interior tags and seams. The guide to reading a suit label applies to coats as well: a fused front, a skimpy seam allowance, or a glued hem tells you the garment is not worth spending on. A good coat has enough inlay at the center back seam to let out an inch, and a tailor can confirm it in a minute.
The Fitting Room Sequence
Check the coat in this order, because each step assumes the one before it passed. Fixing a sleeve on a coat with the wrong shoulders is wasted money.
- Put on the layers you will actually wear, including the bulkiest sweater and a suit jacket if relevant.
- Check the shoulder seam against the bone. If it is off by more than half an inch, stop.
- Raise your arms overhead and watch the hem and collar.
- Button the coat, sit down, and check the front and back for strain.
- Bend your elbows and check the sleeve length with the arm in use.
- Turn the collar up, add a scarf, and check the neck clearance.
- Look at the hem in a mirror from three steps back, with your shoes on.
If the coat passes all seven, buy it. If it fails at step two or three, walk away regardless of the price, because those are the two areas a tailor cannot reliably fix.
Frequently Asked Questions
Should a winter coat be tight or loose?
Loose enough to layer, but not so loose that it loses its shape. Aim for three to four inches of ease at the chest over a shirt and light sweater, or five to six inches over a suit. The coat should feel slightly roomy when you button it indoors, because cold weather and a scarf will fill some of that space.
How do I know if a coat's shoulders are too narrow?
Look for a diagonal crease running from the collar toward the armpit, and check whether the sleeve head lifts when you raise an arm. The seam should sit at or just past the bone at the point of your shoulder. If it sits inside that point, the coat is too small and cannot be fixed economically.
Can a coat sleeve be lengthened?
Sometimes, if the sleeve has a generous hem allowance, but usually not by much. Most coats leave only half an inch to an inch inside the cuff. Lengthening beyond that requires moving the sleeve from the shoulder, which is expensive and changes the armhole. It is better to buy the correct length.
How long should an overcoat be?
A traditional overcoat ends just above or at the knee, roughly 42-46 inches from the base of the back collar for an average-height man. It should cover the hem of a suit jacket underneath. Shorter car coats land mid-thigh at 34-38 inches, while peacoats stop at the hip around 30-32 inches.
Is it worth tailoring an inexpensive coat?
Only if the shoulders and chest already fit and the shell is structurally sound. A $50 hem or $60 sleeve adjustment on a coat you will wear for years is reasonable. Spending $200 to rebuild the shoulders of a cheap coat is not, because the result will still be limited by the original pattern.