3 1.58 cm. 1 wooden ruler refers to one foot of wooden ruler for measuring clothes, which is equal to 0.95 foot of city ruler, equivalent to 3 1.58 cm, so 1 wooden ruler is equal to 3 1.58 cm. Wooden ruler refers to a scale, which indicates the foot of logs with a certain diameter and length, and is used to measure the volume of logs or wood.