Dimensional quantities are represented by symbols, eg M, L, T, which represents the mass (mass), length (length) and time (time). There are two kinds of dimensions are Dimensions of Primary and Secondary Dimensions. Primary dimensions include the M (for unit mass), L (for unit length) and T (for units of time). Secondary dimensions are the dimensions of all the magnitude of derivatives which are stated in Primary Dimensions. Example: Dimension Style: ML T-2 or Acceleration dimensions: L T-2.

Here is a table showing the dimensions and scale of seven basic units in the system of International Units:

Benefit Dimensions in Physics, among others: (1) can be used to prove the two quantities equal to or not. Two quantities equal if both have the same dimensions or both of them including vector quantity or scalar, (2) can be used to determine the equation that must be wrong or may be true, (3) can be used to derive the equation of a physical property if proportionality with the amount of physical quantities such -other physical quantities are known.

Units and dimensions of a physical variable are two different things. Units of physical quantities are defined by treaty, dealing with certain standards (for example, the length scale can have units meters, feet, inches, miles, or micrometer), but only one-dimensional length scale, namely L. Two sets are different can be converted to one another (for example: 1 m = 39.37 in.; figure 39.37 is called a conversion factor), while no conversion factor antarlambang dimensions.