How to Choose the Right T-Shirt Size When Shopping Online
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The Online Shopping Problem That Has Nothing to Do With Style
You've found the right tee. The colour is right, the fabric sounds good, the price works. And then you hit the size selector and the confidence disappears. Is Medium going to be too tight or too loose? Does this brand run large or small? Should you size up just to be safe?
This hesitation is one of the most common reasons online clothing purchases get abandoned entirely — or completed with a size that turns out wrong, leading to an exchange, a return, or simply a garment that gets worn less because it never quite fits right.
The good news is that sizing uncertainty is almost entirely solvable with a small amount of upfront effort. A handful of accurate measurements, cross-referenced against a brand's specific size chart, removes nearly all the guesswork — and takes less time than most people spend scrolling through reviews hoping someone else's experience will tell them what to do.
This guide walks through exactly how to measure yourself correctly, how to read a size chart properly, and how to make confident sizing decisions when shopping for t-shirts and basics online.
Why "I Know My Size" Often Isn't Enough
Most people default to whatever size they typically wear — Medium, Large, whatever it might be — without accounting for the fact that sizing isn't standardized across brands. A Medium from one brand can differ meaningfully in chest width, body length, and shoulder measurement from a Medium at another brand, even within the same general category of casual basics.
This is particularly true when comparing brands with different fit philosophies — a brand built around a slim, closer-cut silhouette will size differently than one built around a relaxed, roomier fit, even if both label their garments with the same size names. Relying on your "usual size" without checking the specific brand's measurements is one of the most common causes of online sizing mistakes.
The Measurements That Actually Matter for a T-Shirt
Rather than guessing based on size labels, taking a few specific body measurements gives you concrete numbers to compare directly against a brand's size chart. This takes about five minutes and dramatically improves the odds of getting the right size on the first order.
Chest Measurement
Wrap a measuring tape around the fullest part of your chest, keeping the tape level and snug but not tight, arms relaxed at your sides. This is the single most important measurement for t-shirt sizing, since chest width is typically the primary differentiator between size categories.
Body Length (Shoulder to Hem)
Measure from the top of your shoulder, near the base of your neck, down to where you'd like the tee to end — typically around the hip. This matters particularly for taller or shorter-than-average builds, where a standard size might fit correctly through the chest but end up too short or too long in overall length.
Shoulder Width
Measure across your back from the edge of one shoulder to the edge of the other, where the shoulder seam would naturally sit. This measurement is especially useful for identifying whether a relaxed or slim fit will suit your frame better, since shoulder placement is one of the most visible indicators of correct sizing.
Sleeve Length (If Relevant)
For any piece with a slightly longer sleeve — some relaxed-fit tees, hoodies — measuring from the shoulder edge down to where you want the sleeve to end helps confirm fit, particularly if you're between standard size breakpoints.
How to Use a Brand's Size Chart Correctly
Always Check the Chart, Even If You "Know Your Size"
Every reputable online clothing brand provides a size chart with specific body or garment measurements for each size label. Cross-referencing your own measurements against this chart — rather than relying on a size label alone — is the single most reliable way to choose correctly, regardless of how confident you feel about your usual size elsewhere.
Understand Body Measurements vs. Garment Measurements
Some size charts list body measurements (the measurements of the person the size is designed to fit), while others list garment measurements (the actual dimensions of the finished product, laid flat). These produce different numbers — a garment measurement will typically be larger than a body measurement to account for ease and comfort. Check which type of measurement the chart is using before comparing it to your own numbers.
Pay Attention to Fit Descriptions
Terms like "relaxed fit," "slim fit," or "regular fit" alongside the size chart provide important context. A relaxed-fit garment in your measured size will generally have more room than a slim-fit garment in the same labelled size, even if the size chart numbers look similar on paper.
What to Do When You're Between Two Sizes
It's common to land between two sizes on a chart — your chest measurement fits comfortably into a Medium, but your preferred body length suggests a Large. In these situations, a few principles help guide the decision:
Consider the Garment's Fit Philosophy
For relaxed-fit basics, sizing down between two options often works well, since the intentional ease in the cut accommodates a slightly smaller size comfortably. For slim or fitted pieces, sizing up is usually the safer choice when between sizes, since a slightly looser fit reads better than one that's genuinely tight.
Think About Your Priority
If chest comfort matters most to you, size toward whichever option better fits your chest measurement. If overall length matters more — particularly relevant for taller builds — prioritize that dimension instead. There's rarely a universally "correct" choice between two close sizes; it depends on which specific fit aspect matters most for how you plan to wear the piece.
Check the Brand's Exchange Policy Before Ordering
When genuinely uncertain between two sizes, checking that easy exchanges are available before placing the order removes much of the risk from the decision. This turns an uncertain choice into a low-stakes one — order your best estimate, and adjust if needed rather than agonizing extensively upfront.
Common Online Sizing Mistakes to Avoid
Measuring Over Bulky Clothing
Taking measurements over a jacket, hoodie, or bulky layer produces inaccurate numbers. Measure directly against your body or over a thin, fitted layer for the most accurate results.
Using an Old or Outdated Measurement
Body measurements can shift over time. If it's been a year or more since you last measured yourself, taking fresh measurements before a significant purchase is worth the few minutes it takes, rather than relying on numbers from memory.
Ignoring Fit Photos and Model Details
Many online listings include details about the model's height and the size they're wearing in product photos. Cross-referencing this against your own height and build can provide a useful additional data point alongside the size chart itself.
Assuming All "Relaxed Fit" Labels Mean the Same Thing
The term "relaxed fit" varies somewhat between brands — always check the actual size chart measurements rather than assuming a shared, universal definition of what "relaxed" means in terms of specific dimensions.
How LAZE Makes Online Sizing Easier
LAZE's relaxed-fit basics are designed with a degree of built-in forgiveness that makes online sizing decisions somewhat more straightforward than fitted or slim-cut alternatives would require.
The Ease Tee's relaxed fit and cotton-spandex construction mean the garment has natural give and comfortable ease built into the cut, which reduces the risk of a size feeling genuinely wrong even if you land slightly off from your ideal measurement match. The V-Neck Tee follows the same relaxed fit philosophy, applying it to a slightly more structured neckline.
The Cloud Hoodie's relaxed, true-to-body cut similarly offers more forgiveness for sizing decisions than a fitted alternative would, particularly useful given that a hoodie is often layered over other pieces and benefits from a small amount of extra room regardless.
Checking the specific LAZE size chart against your own chest, length, and shoulder measurements — following the method outlined in this guide — remains the most reliable way to choose your size with confidence, even with the relatively forgiving relaxed fits across the range.
Frequently Asked Questions
What's the most important measurement for choosing a t-shirt size online?
Chest measurement is typically the primary factor in t-shirt sizing, since it's usually the main differentiator between size categories on most brands' size charts. Body length and shoulder width are also important, particularly for taller, shorter, or broader-than-average builds.
Should I size up if I'm between two sizes?
It depends on the garment's fit style. For relaxed-fit basics, sizing down between two close options often works well due to the built-in ease in the cut. For slim or fitted pieces, sizing up is generally the safer choice when uncertain, since a slightly looser fit tends to look and feel better than one that's genuinely tight.
How do I measure my chest correctly for sizing?
Wrap a measuring tape around the fullest part of your chest, keeping it level and snug but not tight, with your arms relaxed at your sides. Take the measurement in light clothing or directly against your skin for the most accurate result.
Do all brands use the same size labels consistently?
No — sizing varies meaningfully between brands, even within similar garment categories. A Medium from one brand can differ noticeably from a Medium at another, particularly when comparing brands with different fit philosophies (relaxed versus slim, for example). Always check the specific brand's size chart rather than relying on your usual size label.
What should I do if I'm still unsure which size to order?
Cross-reference your measurements carefully against the specific brand's size chart, check the garment's fit description (relaxed, slim, regular), and confirm the brand's exchange policy before ordering. A brand with an easy exchange process significantly reduces the risk of an uncertain sizing decision.
Confidence Starts With the Right Fit
Sizing uncertainty is one of the most solvable problems in online shopping — a few accurate measurements, checked carefully against a brand's specific size chart, remove nearly all the guesswork that leads to returns, exchanges, and pieces that never quite feel right.
Taking five minutes to measure yourself properly before your next online purchase pays off directly: fewer wrong-size orders, less hassle with exchanges, and clothing that actually fits the way it's meant to from the first wear.
LAZE's relaxed-fit basics, combined with a clear size chart, make this process as straightforward as it can be.
Explore the LAZE collection → Find your size, get it right the first time.