The current yield of a bond measures the returns an investor can expect if he holds the bond for a period of one year. It is calculated as the annual interest received divided by the current price of the bond.
The current bond price is the clean price of the bond.
One must note that the current yield represents the return from the bond at a particular time and does not represent the returns over the lifetime of the bond. The current yield also does not take into account the reinvestment risk.
Assume that a $100 par bond is currently trading at $95, and pays a coupon of 6%. The current yield will be given as follows: