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Indus standardized weights

How did distant cities share one standard of weight?

Physics· BC 2600· Mohenjo-daro · Indus standardized weights· Ask

1min readUpdated 2026-09-29

That time, that place

Harappa and Mohenjo-daro on the Indus were carefully planned cities, with gridded streets and covered drains. They lay hundreds of kilometers apart, yet traded with each other — and with Mesopotamia far beyond.

Why this question

Trading across distance runs into one awkward problem: if my scale and your scale disagree, no one can tell who is being cheated. Trust had to begin with weight.

What was found

They cut cubes of stone into weights that doubled — 1, 2, 4, 8, 16. The remarkable part is the precision: weights found in cities hundreds of kilometers apart match almost exactly. Bricks too were standardized at 4:2:1. Someone set a rule, and a vast region kept it.

The old idea

Weight was whatever the scale's owner said it was

The evidence

Weights from different sites match one another

What followed

The Indus script is still undeciphered, so we don't know who set the standard

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