Day count convention is a system used to determine the number of days between two coupon dates. It is important in calculating accrued interest and present value when the next coupon payment is less than a full coupon period. Each bond market has its own daycount convention. In calculating the number of days between two dates, the actual number of days is not always the same as the number of days that should be used in the accrued interest formula. The number of days used depend on the day count conventions for the particular securities. Few of the day count conventions used in the bond market are: A 30/360 day count convention, where 30 days in a month and 360 days in a year are considered; actual / actual day-count convention, where actual number of days in a month and year are considered.