As the name describes the width of your bars refers to the length from bar end to bar end. As you could imagine, the width of the bars has an impact on the way the bike feels. The wider the bar the less force is required to turn, however, the more movement is required to turn the bar. Therefore the larger the bar the more stable the rider should feel. On the end of the spectrum the smaller the bars the less stable the bile will feel and the less movement the rider needs to make to turn. However narrow bars can also mean less stability when riding at speed. As a general rule of thumb, the width of the bars should be similar to your shoulder width.