Step 1: Wrap a thin strip of paper around the finger you want to wear the Mettle & Bloom ring on.
Step 2. Mark the point where the paper overlaps.
Step 3: Straighten the piece of paper over a ruler and read the measurement in mm.
53mm = size 6 (L)
55mm = size 7 (N)
57.5mm = size 8 (P)
Method 2:
Step 1: Place a ring you already own on a ruler
Step 2: Measure the INSIDE diameter of that ring in mm (do this by measuring a straight line through the rings centre).
16.77mm = size 6 (L)
17.5mm = size 7 (N)
18.3mm = size 8 (P)