Measuring yourself (body): Measure across your chest from armpit to armpit, then pick the size above your number for a loose fit.

Measuring a garment (laid flat): Lay a similar top that fits you on a flat surface, measure straight across from armpit to armpit, and pick the size that matches your number. No need to add anything.

Length: front length, from the high point shoulder (HPS), the top of the shoulder seam next to the collar, down to the hem.

Measured before washing, ±2cm.