A panel gauge is essentially a larger version of the marking gauge. It has a much longer stem, fence and a bigger pin for marking the wood.
The main use for panel gauges is to mark large wooden boards to widths, for example when marking out doors, windows and cupboards.
They are also useful if you need to mark the centre of a piece of wood, as the long stem allows you to reach over the majority of the board.
As panel gauges are used for large scale marking, they have a very different purpose to other marking out tools, which mark small lines for intricate cuts in joinery and chisel work.
Panel gauge sizes
Panel gauge stem lengths can vary from 420mm (16.5″) to 750mm (25.9″). The size you use will depend on how large a sheet of material you are using.
As you can see, panel gauges are at least twice the length of marking gauges.