From Traderpedia

Definition: Total earnings divided by the number of shares outstanding.

Earnings per share(EPS) is the earnings returned on the amount invested initially.

EPS is calculated as bottom line net income divided by the number of shares outstanding.

The value used for company earnings can either be the last twelve months' net income (referred to as trailing-twelve-months, or ttm), or analysts' predictions for the next twelve months' net income (referred to as forward).

The number of shares used for the calculation can either be basic (only shares that are currently outstanding) or diluted (includes all shares that could potentially enter the market).

Companies often use a weighted average of shares outstanding over the reporting term. EPS can be calculated for the previous year ("trailing EPS"), for the current year ("current EPS"), or for the coming year ("forward EPS"). Note that last year's EPS would be actual, while current year and forward year EPS would be estimates.