To measure your horse it is helpful to have an existing rug that fits well. If possible lay it flat and measure from the front edge, along the side to the back edge. If this is not possible please:
Measure from the centre of the horse’s chest to a line vertical with the top of the tail as shown in picture.
To measure your horse for a neck piece, you must measure along the neck, from the poll, to just beyond the withers.
Neck Pieces Measure:
Full - 37"