Square Wood Rule or Calculating Stick

This large wood rule has a square cross-section and rounded edges. Metal plates are screwed into both ends. The rule is covered with numbers placed at one-inch intervals. One corner is numbered by ones from 1 to 60 and labeled "Height." "Wood Rule" is written above the scale. Adjacent to the 11 on this scale are listed 15 "Widths" in intervals of one inch, ranging from 3'2" to 4'4". Next to each Width, and adjacent to the numbers 12–60 on the Height scale, are lists of numbers. Each number is eight times the product of the height and width, with both of these taken in feet (i.e., the 12 is assumed to represent one foot). The numbers in the lists are rounded off to the nearest whole number.
The National Museum of History and Technology, now the National Museum of American History, acquired this calculating stick, probably between 1962 and 1965, for its Growth of the United States exhibition, which opened in 1967 and closed in 1982. What the original owner was measuring with these calculations is not known.
Reference: William S. Walker, "A Living Exhibition: The Smithsonian, Folklife, and the Making of the Modern Museum" (Ph.D. diss., Brandeis University, 2007).
Currently not on view
Object Name
calculating rule
date made
19th century
Physical Description
wood (overall material)
metal (overall material)
overall: 2.8 cm x 154.4 cm x 2.8 cm; 1 3/32 in x 60 25/32 in x 1 3/32 in
place made
United States
ID Number
accession number
catalog number
Rule, Calculating
See more items in
Medicine and Science: Mathematics
Science & Mathematics
Scale Rules
Data Source
National Museum of American History, Kenneth E. Behring Center


Add a comment about this object