A blade (10) for a rotor of a wind turbine having a profiled contour divided into: a root region (30), an airfoil region (34), and a transition region (32) between the root region (30) and the airfoil region (34). A shoulder (40) is located at the boundary between the transition region (32) and the airfoil region (34). The blade's profiled contour comprises a local relative thickness defined as the local ratio between a maximum profile thickness (t) and the chord length (c). The ratio between the shoulder width (W) and the blade length (L) being less than or equal to 0.075, and the relative thickness (t/c) in a blade length interval of 0-0.8L is at least 22%.