Our fabric has plenty of stretch, so you'll likely fit comfortably across more than one size - it really comes down to how you like your shirts to fit.
For example, if you're a size 10:
S / 8–10 → choose this for a closer fit
M / 10–12 → choose this for a more relaxed fit
If you’re unsure, we recommend choosing the size that matches how you prefer your clothes to fit, rather than stressing over the number.