A handle for a hand-guided power tool has a shaft with a fastening end and a free end. The fastening end is provided to secure the handle on the power tool. The handle has an outer side that is designed to at least partially support a palm of a hand of a user. An inner side is positioned opposite the outer side at the handle. A thumb support surface is provided at the inner side. The thumb support surface, viewed in a side view of the handle perpendicular to the inner side, is positioned at an angle of at least 20° and at most 70° in relation to a longitudinal axis of the handle at every point of the thumb support surface. A power tool such as a trimmer has a handle bar provided with a handle with such a thumb support surface.