Many people are familiar with an intelligence test to determine your intelligence quotient (IQ).  Some say this is related to how smart you are.  Although it could be just a measure of how good you are at tests

Those that are truly smart avoid tests.  Now that is a demonstration of high IQ behavior if you ask me.

What is EQ

It has been postulated that to rise to leadership roles in an organization (e.g. Corporate, Political or Educational) the level of intelligence (IQ) sets the price of entry but your level of emotional intelligence (sometimes equated to maturity) determines how effective a leader you are and the maximum  amount of EQ is needed if you expect to rise to the highest level of leadership.

Emotional intelligence is directly determined by your behavior.  Specifically how you react in a specific situation.  For example, when under great stress or when being critcized.  Additionally, you are keenly aware of yourself, how you are feeling and thinking, to the extent you can fully control your behaviour at any point in time, ensuring the best choices rather than those that might be driven by emotional overrides.

Can I measure it?

There are self tests available but often the answers that will lead to assesment of a high EQ (ie the right answers) are readily apparent.

The best measure is independent feedback.  This is best when be provided by anonymous surveys managed by an independent party.  The questions are carefully crafted and then interpreted and scored.  In essence this method tells you how others view your level of EQ, which by the very nature of what EQ represents is all that really matters.

What is even more fun is when you complete the survey as well as others who know and interact with you regularly.  Then compare results. Basically a disconnect between what you think of yourselve and what others think of you is usually a clue.