Conversion factors are used in solving problems in which a certain measurement must be expressed with different units.

When a given measurement is multiplied by an appropriate conversion factor, the numerical value changes, but the actual size of the quantity measured remains the same.

A conversion factor is a ratio of equivalent measurements.

Dimensional analysis is a technique that uses the units (dimensions) of the measurement in order to correctly solve problems.

The metric systemâ€™s use of powers of 10 for all conversions makes this quite simple.