To measure the size of an ihai, only the fudatake (height of the flat tablet part where characters are inscribed) is measured and its size is represented in 'go'; for example, four go of ihai has approximately twelve centimeters of the fudatake.
寸法は札丈（札板文字を入れる板の部分の高さ）を測り、「号」で表される（例：4.0号＝札丈が約12cm）。