The heel-to-toe length of an iron head, measured along the ground line from the hosel out to the farthest point of the toe. Most iron heads run roughly 2.9 to 3.4 inches, and a tenth of an inch is plainly visible at address. A longer blade spreads mass wider from the center, raising MOI and forgiveness on off-center strikes — which is why game-improvement irons stretch long and players blades stay compact. The trade: a short blade slips through rough cleaner, sits with less offset, and rewards a precise strike, while a long one buys stability at the cost of a chunkier look. Designers pair blade length with offset and topline thickness, so the three tend to grow or shrink together.