Abstract: A measuring tape radius marking tool includes a block having an open-faced slot. A cut-out is formed in the block generally opposite the slot for holding non-circular markers. An aperture is formed through the block between the slot and the cut-out so as to be aligned with the cut-out for receiving generally circular markers. A portion of a measuring tape corresponding to the distance to be measured from a center point to form a radius marking is disposed within the slot and secured in place. A marker is inserted into either the cut-out or aperture, secured in place, and the tool is moved in an arc to create the measured radius marking.