How To · Fashion · Basics
How to Read a Size Chart and Actually Understand It
Size charts aren't mysterious—they're a conversation between you and the brand. Here's how to read them like someone who knows what they're doing.
5 min read · IrisYou've found the perfect shirt online. The photos look right. The price is fair. Then you hit the size selector and freeze. Is it S or M? Does this brand run small? Will it shrink? The size chart sits there, a grid of numbers that might as well be written in code.
Here's the truth: size charts aren't complicated. They're just measurements in inches or centimeters—the actual dimensions of the garment itself. Once you know how to read one and how to measure your own body, you'll order with confidence instead of hope.
Size charts measure the garment, not your body. That's the distinction that changes everything.
What you'll need.
- 01Soft measuring tape (cloth, not metal)
- 02Pen and paper or notes app
- 03A well-fitting shirt you already own (for reference)
Step one · 2 minutes
Understand what you're looking at
A size chart shows the physical dimensions of a garment—chest width, sleeve length, shoulder width, torso length. These are measurements of the folded or laid-flat shirt, not how it will feel on your body. Every brand measures differently. One brand's M might be another's L. The chart is the brand's promise of what you're ordering, nothing more.
Look for a diagram on the size chart that shows which measurements correspond to which parts of the garment. If there's no diagram, scroll down or check the product description.
Step two · 2 minutes
Measure your chest
Use a soft measuring tape (not a ruler). Wrap it snugly around the fullest part of your chest, keeping it level and parallel to the ground. Don't pull tight—you should be able to fit one finger under the tape. Write down the number in inches or centimeters, depending on what the chart uses. This is your baseline measurement.
Measure yourself in a fitted t-shirt or bare-chested. Loose clothing will throw off your numbers by an inch or more.
Step three · 1 minute
Check the chest width on the chart
Find the chest or bust measurement on the size chart. Compare your measurement to the listed sizes. If your chest is 38 inches and the chart shows S at 36–37 inches and M at 38–40 inches, the M is your fit. Don't overthink it—you're looking for the size range that contains your measurement.
If you're between sizes, consider the fit you prefer. Prefer a closer fit? Size down. Like room to move? Size up. The chart tells you what to expect either way.
Step four · 2 minutes
Verify sleeve length and shoulder width
Chest size alone isn't the full story. Measure from the center back of your neck, across your shoulder, down to your wrist with your arm at your side—this is your sleeve length. Also measure from shoulder point to shoulder point across the back. Compare these to the chart. A shirt can fit your chest perfectly but have sleeves that are too short or shoulders that are too wide.
If you're tall or have long arms, pay extra attention to sleeve length. It's one of the hardest things to alter after purchase.
Step five · 2 minutes
Look for fit notes and material specifics
Many size charts include text like 'runs small' or 'generous fit' or 'pre-shrunk.' Read this carefully. If a chart says the fabric shrinks 3%, size up accordingly. If it says the fit is 'oversized,' compare that to how you actually want the garment to sit. These notes are the brand's way of telling you what they know about their own products.
Check the fabric content too. Cotton shrinks more than synthetics. Linen wrinkles but doesn't shrink much. This affects whether you should size up or account for changes after washing.
Step six · 1 minute
Cross-reference with reviews if available
After you've matched your measurements to the chart, glance at customer reviews. Real buyers often mention fit—'runs small,' 'perfect fit,' 'too boxy.' This is the lived experience of the garment, not the promise. One or two reviews saying 'size up' can confirm what the chart already suggested.
Ignore reviews that just say 'great shirt' without mentioning fit. Look for specific feedback from people with similar builds to yours.
How to know you've read it right.
You've read the chart correctly when your measurements fall within the size's range and you understand why you chose that size. You should be able to explain: 'I'm a 39-inch chest, so I ordered M because the chart shows M at 38–40 inches. The sleeves are 33 inches, which matches my arm length.' That clarity is the goal.
Questions at the mirror.
What if the size chart uses centimeters and I measured in inches?
Multiply your inches by 2.54 to convert to centimeters. Or measure again in centimeters using a metric measuring tape. Most online converters are accurate, but re-measuring takes 30 seconds and removes doubt.
The chart shows two measurements for chest—which one do I use?
That's usually the range for that size. If it shows '38–40,' the garment is designed to fit chests from 38 to 40 inches. Pick the size where your measurement falls comfortably in the middle of the range.
I can't find a size chart on the product page.
Scroll to the bottom of the product description or look for a 'Size Guide' link. If it's not there, email the brand or check their main website for a universal size chart. Never order from a brand with no size information.
The chart says 'oversized fit' but I like fitted clothes. Should I size down?
Not necessarily. Measure the garment's actual width and compare it to a fitted shirt you own and love. If the oversized shirt is still within 1–2 inches of your fitted shirt, it might work. If it's 3+ inches wider, sizing down might help—or that brand's aesthetic just isn't for you.