“Wide” is a label. Millimetres tell the truth.
Your boot needs enough room without forcing you onto more board than necessary. Start with waist width, then account for the boot’s outer length and your binding angles.
UK BOOTWAIST WIDTHLIKELY LABEL
UK 2–6.5About 238–248 mmNarrow to regular
UK 7–9About 248–255 mmRegular
UK 9.5–10.5About 255–260 mmMid-wide
UK 11+About 260 mm+Wide
Three things that change the answer
- Low-profile snowboard boots can fit narrower boards.
- Stronger binding angles reduce how far the boot projects across the board.
- Board width under each binding is greater than its narrowest waist measurement.
For aggressive carving or unusually large boots, ask a competent snowboard shop to check the assembled boot and binding overhang.