How did everyday commodities come to be standardized? Ca. 1920, manufacturers made beds in 78 sizes and produced dozens of styles of electrical plugs and outlets. By 1930, they made four standard bed sizes, and outlets and plugs had been completely standardized. How did this transformation happen—and happen so rapidly? The (often implicit) conventional account portrays product standardization—an essential precondition of mass production—as natural and inevitable. Once the benefits of mass production became apparent, manufacturers simply limited their product lines so that they could manufacture fewer products in higher volumes. But the standardization of everyday commodities was not a natural market outcome. Manufacturers were under too much competitive pressure to unilaterally disarm when product differentiation gave them an essential competitive advantage. The rapid standardization of everyday commodities in the 1920s, this paper shows, was the result of determined intervention—a big “nudge”—by the federal government in the 1920s. Building on WWI efforts, the Department of Commerce launched the “Division of Simplified Practice” to persuade and enable manufacturers to pursue standardization collectively. Out of its work came the standardization of bed sizes, electrical plugs, and a host of everyday commodities.