The best replacement for millimeters is inches.

The best alternatives to millimeters are rated as following:
★★★★★  inches
★★★★★  centimeters
★★  ounces
★  meters
★  1 meter
★  centimeters which is larger
★  millimetres
  100 centimeters
  50 centimeters
  micrometers
  caliber
  milligrams
  meters bigger
  teaspoons
  microns

Your alternative for millimeters is not listed? Suggest!
Speaking about millimeters, one probably shouldn't forget about ruler.

Other search terms related to millimeters and their ratings are:
★★★★★ ruler
★ centimeters
You have in mind a companion for millimeters and it is not yet here? Propose!



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millimeters
inches
centimeters