In our previous studies, a set of convienient formulas useful for any dimensions of notches in a round specimen were proposed for a notch opening angle of 60 degree. In this study the effect of notch opening angle on the stress concentration factor is considered. First, for the limiting cases of shallow notches, the body force method is used to calculate the SCFs with varying the opening angle from 0 to 90 degree; then, the formulas are obtained as Kts for any root radius. Second, for the limiting cases of deep notches, the body force method is used to calculate the SCFs with varying the opening angle from 0 to 90; then, the formulas are obtained as Ktd for any root radius. Third, for general notches the effect of opening angle is considered. Finally, a set of convenient formulas useful for any shape of notch in a round test specimen are proposed for the opening angle from 0 to 90 degree. The formulas yield SCFs with less than 1% error for any shape of notch in most cases under tension.