A putter head has a front that strikes a golf ball during putting, a length a, a width b, a weight W, and a moment of inertia I. The width extends along a horizontal width axis perpendicularly intersecting the front of the putter head. The length extends along a horizontal length axis perpendicularly intersecting the horizontal axis. The dimensions are, for example, a≦7 inches, b≦a, and I/Wa2>0.30.