Volume is a measure of the number of shares traded in any market, market volume can be calculated by the number of units traded multiplied by the share price.
Volume is calculated for a specific time frame, so let’s suppose for a 1 hour period,1200 shares were transacted in the exchange, then we can say that the volume was 1200 shares.
Market exchanges track trading volumes daily. Volume also reflects pricing momentum. When market activity — i.e., volume — is low, investors anticipate slower moving (or declining) prices. When market activity goes up, volume typically moves in the same direction.