How To · Fashion · Wear
How to choose the right button-up for your body
A well-fitting button-up is the foundation of business-casual dressing—but fit means different things depending on your proportions. Learn which details matter most for your frame.
5 min read · IrisThe button-up is non-negotiable in business-casual wardrobes, but it's also one of the trickiest pieces to fit properly. Unlike a sweater that can hide minor proportion mismatches, a button-up broadcasts every fit misstep—gaping buttons, pulling fabric, sleeves that swallow your hands, or a hem that hits at an awkward angle.
The good news: fit isn't one-size-fits-all, and knowing your proportions means you can shop with confidence instead of trying on dozens of options. Start by identifying where your body needs the most support, then prioritize those measurements when evaluating a shirt.
Shoulders are non-negotiable. If the seam sits past your shoulder point, the entire shirt will feel sloppy, no matter how well the chest fits.
What you'll need.
- 01Soft measuring tape
- 02Mirror (full-length preferred)
- 03Button-up shirts to try
- 04Phone camera
Step one · 2 minutes
Measure your shoulder width
Stand straight and have someone measure across your back from the outer edge of one shoulder bone to the other. This is your true shoulder width. Button-up shoulder seams should sit exactly at this point—not forward, not back. If you have narrow shoulders (under 16 inches), look for petite or fitted cuts. If you have broad shoulders (over 18 inches), seek out tailored or relaxed fits designed for larger frames. This single measurement is your anchor point for all other fit decisions.
Wear a fitted tank or t-shirt when measuring so the tape sits flush against your body.
Step two · 2 minutes
Check the button placement across your chest
Button-ups should close smoothly without pulling or gaping between buttons. If you're full-chested, look for shirts with buttons spaced slightly wider apart or cut with extra room in the bust. If you're smaller in the chest, standard button spacing works fine—just ensure the fabric doesn't bunch. The easiest test: button the shirt and look down. You shouldn't see any X-shaped pulling or daylight between buttons. If either happens, the shirt is too tight or too loose in the chest.
Try the shirt buttoned all the way up to assess chest fit—this is where most gaping problems show up.
Step three · 2 minutes
Verify sleeve length and fit
Sleeves should end at your wrist bone when your arms hang naturally at your sides. If they're too long, they'll bunch at your wrists and look unfinished; too short and you'll expose too much forearm. For sleeve width, there should be enough room to bend your elbow comfortably without the fabric pulling, but not so much that it balloons around your arm. If you have very slender arms, petite cuts or fitted styles prevent excess fabric. If you have fuller arms, look for relaxed or tapered sleeves that provide room without looking oversized.
Roll or cuff the sleeves to your elbow for a polished business-casual look, but only if the base length is correct.
Step four · 2 minutes
Assess the waist and torso length
A button-up should skim your torso without clinging or billowing. If you have a defined waist, a fitted or tailored cut will highlight it; if you prefer a straighter silhouette, a relaxed or boyfriend cut works better. Check torso length by standing and letting your arms hang—the hem should hit at your hip bone or just below, never mid-thigh. If you're petite, standard lengths often swallow you; seek petite-specific cuts. If you're tall, regular lengths may ride up; consider extended or tall sizes.
Tuck the back in slightly when trying on to see how the shirt would look half-tucked, a common business-casual styling choice.
Step five · 1 minute
Test the fabric and collar for your frame
Fabric weight and collar style affect how a shirt flatters your proportions. Stiffer fabrics hold structure better on larger frames; lighter fabrics drape more gracefully on smaller frames. Collar size matters too: a wide spread collar can overwhelm petite faces, while a narrow collar might look too small on broader shoulders. Try on a few collar styles and take a photo—sometimes the camera reveals what the mirror doesn't.
Avoid overly stiff fabrics if you plan to tuck the shirt; they create bulk at the waist.
Step six · 1 minute
Make the final call
If the shoulders fit perfectly but the chest is slightly tight, tailoring the chest is expensive and often imperfect. If the shoulders fit and the chest is slightly loose, that's workable—you can always have the sides taken in. If the shoulders don't fit, walk away; this is the one measurement that's nearly impossible to alter well. A good-fitting button-up should feel comfortable enough to wear all day without adjusting or tugging.
Keep a note of your measurements and preferred fits so you can shop online with confidence.
How to know it works.
A well-fitting button-up should feel invisible—no pulling, no gaping, no constant tugging. You should be able to button it fully, move your arms freely, and sit comfortably without the fabric shifting. The shoulders sit exactly at your shoulder points, the chest closes smoothly, and the hem hits your hip or just below.
Questions at the mirror.
What if I'm between sizes?
Always size for the shoulders first. If the shoulders fit but the chest is slightly loose, have the sides taken in. If the shoulders fit but the chest is too tight, size up and have the sides tailored. Shoulders are nearly impossible to alter well, so they're your priority.
Should I size differently for different fabrics?
Yes. Stiffer fabrics like structured cotton hold their shape and can feel tighter; softer fabrics like linen or cotton blends drape and may feel looser. Try on both and compare fit, not just size number.
How do I account for washing and shrinkage?
Most quality button-ups shrink slightly in length and width. Check the care label and ask the retailer about preshrinking. If unsure, size up slightly in length and have the hem tailored after the first wash.
Is a boyfriend fit right for me if I have a curvy body?
Boyfriend cuts can work on any body type, but they work best when tailored at the sides and waist. If you prefer a more defined silhouette, a fitted or tailored cut will serve you better without requiring alterations.