By StephanieV. July 23rd, 2014

A recreation of an ancient Indus trader using weights to weigh goods (left, by Jonathan Mark Kenoyer), cubical weights in graduated sizes from Allahdino (top right) and Harappa (bottom right). These weights conform to the standard Harappan binary weight system that was used in all of the settlements. The smallest weight in this series is 0.856 grams and the most common weight is approximately 13.7 grams, which is in the 16th ratio (e.g. they increased in ration 1:2:4:8:16:32). In the large weights the system become a decimal increase where the largest weight is 100 times the weight of the 16th ratio in the binary system. These weights were found in recent excavations at Harappa and may have been used for controlling trade and possibly for collecting taxes.

See the famous article on the derivation of Indus weight ratios, Weights at Chanhu-daro by A.S. Henny.