CM1, CM-1 or cm−1 may refer to:
The Chelmsford postcode area Bowers & Wilkins (B&W) CM1 loudspeaker A primary school grade in the French educational system Cooking Mama, the first game in the Cooking Mama series Cake Mania, the first game in the Cake Mania series The Panasonic Lumix DMC-CM1 smartphone Connection Machine Model 1, a parallel computer USS Baltimore (CM-1), a United States warship
In the form cm−1, it may refer to: Inverse centimetre, unit of measurement: see Reciprocal length