Abstract: The invention is an adjustable wrench comprising a stationary arm with a terminal end and a grip end, the terminal end defining a lower bolt claw. A ratchet arm is slidably coupled to the stationary arm, the ratchet being movable to control the movement of upper and central bolt claws. The upper, central, and lower bolt claws are fitted to the shape of a standard hexagonal bolt head, being adjustable to different sized bolts upon up or down movement of the ratchet arm relative to the stationary arm. The central bolt claw is fitted through a slot in the upper bolt claw which defines an inclined ramp surface such that movement of one claw is coupled to movement of the other claw. The claws move cooperatively in reaction to the stationary, lower bolt claw to form a tightly fitted surface for a bolt head. The stationary arm has a complex profile on its lower surface for contact with a ratchet pawl pivotally attached to the ratchet arm.