Most men buy t-shirts the way they bought them at eighteen, by grabbing whatever size is written on the tag of the last shirt that did not embarrass them. That works until the fabric changes. A 420 GSM heavyweight tee behaves nothing like a 150 GSM fast fashion shirt, and the size that fit one will not always fit the other.

This guide shows you how to size a heavyweight t-shirt using two numbers you already know: your height and your weight.

Start with height and weight, not your old size

Chest measurement is the traditional way to size a shirt, and it is useful, but it misses something. Two men with a 44 inch chest can need different sizes if one is 5'7" and the other is 6'2". Height changes where the hem sits, where the sleeve ends, and how much fabric has to travel across the torso.

Height and weight together capture more of that. Here is the chart TGTHR built from customer data. Find your height band, then the weight range you fall into.

All weights in pounds. The TG1 runs M to 3XL.

Why heavyweight fabric sizes differently

Fabric weight is measured in grams per square metre. A typical mass market tee sits somewhere between 140 and 180 GSM. A midweight tee is roughly 180 to 220. Anything at 250 and above is genuinely heavyweight, and the TG1 is 420 GSM, which is 12.4 ounces.

That weight changes three things about fit.

1. Heavy fabric hangs instead of clinging

Thin jersey follows the body because it has no structural weight of its own. It maps whatever is underneath it. Heavy jersey has enough mass to fall away from the body between contact points, so it skims rather than grips. This is why a heavyweight tee often looks more flattering on a larger frame than a thin one does, even at the same nominal size.

2. Heavy fabric does not stretch to forgive a bad size

A thin shirt that is half a size too small will stretch and cope. A 420 GSM shirt will not. It will simply be too small. That makes getting the size right more important, not less.

3. Heavy fabric holds its shape through the wash

Light shirts lose their collar and their hem within a season. Denser fabric resists that, so the size you buy is closer to the size you keep.

Where most men get it wrong

Buying for the chest and ignoring the waist

Plenty of men size up until the chest is comfortable, then live with a shirt that billows at the waist. A shirt engineered per size handles this differently. The TG1 is cut with a roomier hem opening so the shirt sits loose at the waist without bunching or riding up, and slimmed through the midsection without compressing it.

Assuming sizes scale evenly

Most brands grade sizes from a single template, taking one sample size and scaling every measurement up and down by fixed ratios. It is cheap and it is fast, and it assumes a 2XL body is an M body at larger scale. It is not. Shoulder width, arm proportion and midsection volume do not increase at the same rate.

TGTHR writes individual sizing rules for each size rather than grading from one template, which is why the recommendation above comes from real customer data rather than a formula.

Check the sleeve and the collar, not just the body

Two details tell you quickly whether a t-shirt was designed or simply scaled.

The sleeve. On a graded shirt the sleeve opening widens with every size, so larger sizes end up with sleeves that swallow the arm. A designed sleeve tapers to follow the arm at each size.

The collar. A collar that stretches out after a few wears was built from ribbing too light for the body fabric. On a heavyweight shirt the collar has to be built to match, or the weight of the body pulls it open.

Frequently asked questions

What size t-shirt am I if I am 6'0" and 200 pounds?

On the chart above, 5'11" to 6'0" at 185 to 210 pounds is an L. If you prefer more room through the midsection, size up to XL.

Should I size up in a heavyweight t-shirt?

Only if you are between two sizes. Heavyweight fabric does not shrink to fit or stretch to forgive, so sizing up two sizes to get a relaxed look usually produces a shirt that is too long, not one that drapes better.

Do heavyweight t-shirts shrink?

100 percent cotton will move a little on first wash. The TG1 goes through a 5-step wash process before it ships, which breaks the fabric in beforehand and reduces how much it moves later. Wash cold and skip the hot dryer and the shift is minimal.

What sizes does the TG1 come in?

M, L, XL, 2XL and 3XL, in six colours: Black, White, Khaki, Rich Blue, Heather Gray and Charcoal Gray.

If you are still unsure, the interactive size finder on the TGTHR size guide takes your height and weight and returns a single recommendation, and every order is covered by a 30 day return window with a free return label.