The industrial scale was a system used to rate the extent of industrial development on different planets.

There were two scales in use. One was a numbering scheme that went at least as high as 7, where higher numbers denoted a greater degree of industrialization. An example of a Level 7 world was Scalos. (TOS: "Wink of an Eye")

The second industrial scale used a letter system:

• B: Earth equivalent 1485
• G: Earth equivalent 2030

During the mid-23rd century, the planet Sigma Draconis III was a grade "B", and the planet Sigma Draconis IV was a grade "G". (TOS: "Spock's Brain")