Check your Project Defaults (File > Project Defaults). There is a Default Grid Factor. It is used to scale grid coordinates to ground coordinates. This is an excerpt from the Help topic:
Grid Factor
Specifies the grid factor. Multiplying a ground measurement by the Grid Factor produces a grid measurement. The Grid Factor applies to horizontal distances, which include arc lengths, tangent distances, chord lengths, radii, stationing, offsets, and slopes/gradients. (Slopes are affected because they involve a horizontal component.) Other computations that involve the Grid Factor include spiral constants, areas, volumes, and rate of change/K values.
If you find its not 1, try setting it to 1. You might want to see if some survey person has dictated that this value is correct, however.