A size chart is a translation, not a guarantee. Two pieces labelled M can measure the same across the chest and still fit completely differently, because the cut decides where the extra room sits.
Measure yourself once, properly
Soft tape, light clothing, tape level all the way round. Chest and bust at the fullest point. Waist at the narrowest part of the torso. Hip at the fullest point, roughly eight inches below the waist. Write them down; they will not change often.
Then measure something you own
This is the step most people skip and it is the useful one. Lay a jumper you like flat, measure it pit to pit and double the number. That is the garment chest. Compare it to the chart rather than comparing your body to the chart.
Cut matters more than size
A relaxed or oversized cut adds several inches of ease on purpose. A fitted or bodycon cut takes them away and relies on stretch. Same label, different result.
Between two sizes
On something structured — a coat, a blazer, a boot — take the larger one. On something with stretch, take the smaller. On a dress you plan to wear over tights, take your usual.
And the honest part
Our size guide is a starting point, not a promise. Where a piece runs large or small we say so on the product page, and if you are unsure, email us with the piece and your usual size and we will tell you what we would take.