T-shirts are in Unisex sizing.

Most customers choose their standard unisex size for a regular fit or go 2 sizes up for an oversized look.

Keep in mind there may be a 1.5" difference in measurements, so if you're unsure between 2 sizes, go for the larger size.

In the video the model is 5'7", wears S for a regular fit or XL for an oversized fit.