How To · Fashion · Build
Find Your Perfect Fit in Basics
A well-fitting basic is the foundation of every outfit—but fit is personal, not one-size-fits-all. Here's how to identify what actually works on your frame.
5 min read · IrisBasics are called basics for a reason: they're supposed to disappear into your wardrobe and work with everything. But a basic that doesn't fit your body is just a garment taking up space. The difference between a top that feels like an extension of yourself and one that feels borrowed comes down to three measurable points: where the shoulder seam sits, how the sleeve hits your arm, and whether the torso length honors your proportions.
Unlike trend pieces, basics demand precision. You're not buying them for novelty—you're buying them to repeat. That means it's worth spending ten minutes in the fitting room actually assessing fit instead of just pulling something on and hoping.
The shoulder seam should sit exactly where your shoulder ends, not drift toward your neck or collapse down your arm.
What you'll need.
- 01A mirror with side and back views
- 02Jeans or pants you normally wear
- 03Your regular bra
- 04A fitting room with space to move
Step one · 2 minutes
Check the shoulder seam placement
Stand in front of a mirror and locate where your shoulder bone ends—this is roughly where the top of your arm begins. The seam of the shirt should sit right at that point, not creeping toward your neck or sliding down your bicep. If the seam is too far inward, the top will bunch at your underarm and restrict movement. If it's too far out, the sleeve will hang awkwardly and the neckline will gape. This single detail determines whether a basic looks intentional or sloppy.
Ask a friend to look at you from the side while you're in the fitting room. Shoulder seams are easier to spot from a profile view.
Step two · 2 minutes
Measure sleeve length against your arm
Raise your arm to a 90-degree angle, elbow bent. The sleeve should hit right at your wrist bone—not covering your hand, not stopping mid-forearm. When your arm is down at your side, the sleeve hem should graze your wrist without pulling or bunching. Sleeves that are too long make you look smaller and create excess fabric at the cuff. Sleeves that are too short expose too much arm and read as unfinished. This matters more in basics because you'll wear them constantly and notice the imperfection every time.
Wear the same bra you normally wear when trying on basics. A different bra can shift how the armhole and sleeve sit on your body.
Step three · 2 minutes
Test the torso length and width
Tuck the top into your jeans or pants (or pretend to) and assess the length. For a fitted basic, the hem should hit right at your hip bone or just below—long enough that it doesn't ride up when you move, short enough that it doesn't overwhelm your frame. For an oversized basic, it should hit mid-hip at minimum. Now check the width: the top should skim your body without clinging or tenting. If you're between sizes, consider your lifestyle. Do you tuck? Do you layer? A slightly looser basic works better for layering; a fitted one is more versatile for tucking.
Sit down in the fitting room. A top that fits standing might pull across your chest or back when you're seated.
Step four · 1 minute
Check the neckline and armhole comfort
The neckline should sit flat against your collarbone without gaping or choking. The armhole should allow you to raise your arm without the fabric pulling at your underarm or shoulder. If you feel restricted or if the armhole creates a visible bulge under your arm, the top is too small in the chest. This is a common fit problem that people ignore because they think they need to size up overall—but sometimes it's just the armhole construction that doesn't work for your body shape.
Raise both arms overhead and do a few shoulder rolls. If you feel any pulling or restriction, keep looking.
Step five · 2 minutes
Walk around and move in the top
Don't just stand still in the fitting room. Walk, reach, bend, sit. A top can look perfect standing motionless and feel terrible when you actually live in it. Pay attention to whether the hem rides up when you raise your arms, whether the neckline shifts, whether you feel self-conscious about any part of the fit. Basics are about ease and invisibility—if you're thinking about how the top fits while you're wearing it, it's not the right fit for you.
Spend at least two minutes moving around. Your body changes position constantly throughout the day.
Step six · 1 minute
Make a final decision based on your lifestyle
If the fit checks out on all five points above, consider whether this top fits into your actual life. Will you wear it weekly? Can you wash it without it shrinking or losing shape? Does the fabric feel good against your skin? Basics are an investment in repetition, so buy only the ones you'll genuinely reach for. A perfectly fitting basic you never wear is just expensive clutter.
If you love the fit but the color or fabric doesn't excite you, keep looking. There's always another basic.
How to know it works.
The right basic disappears. You put it on and forget about it—no tugging, no adjusting, no self-consciousness. You can move freely, the proportions feel balanced on your frame, and you reach for it repeatedly. That's when you know the fit is right.
Questions at the mirror.
The shoulder seam is perfect but the armhole is tight. Should I size up?
Not necessarily. Armhole tightness is often a design issue, not a size issue. Try a different brand or style—some basics have roomier armholes by construction. Sizing up might fix the armhole but throw off the shoulder seam and sleeve length.
I'm between sizes. Should I buy both and return one?
Only if you're genuinely torn. If one size is clearly better in the shoulders and sleeves, that's your answer. Basics are about fit precision, so choose the size that nails at least three of the five checkpoints.
The top fits perfectly but shrinks after washing. What do I do?
Check the care label before you buy. If it's prone to shrinkage, size up slightly to account for it, or buy a brand known for stable fabrics. Fit is only perfect if it stays perfect.
I have broad shoulders. Should I always buy a larger size?
Not if it throws off the sleeve length and torso fit. Look for brands that offer extended shoulder widths or styles cut with broader shoulders. Sizing up across the board creates other fit problems.