It is remarkable that gender inequality in the United States, the largest economy in the world, remains so high. While many argue that gender equality is the “right” thing to do, it is now clear that equality is also economically the “smart” thing to do. New research by the McKinsey Global Institute (MGI) finds that every U.S. state and city could add at least 5% to GDP by 2025 by advancing the economic potential of women. Half of U.S. states could add more than 10%, and the nation’s 50 largest cities could add between 6% and 13% of GDP. We found that about $2.1 trillion could be added to the country’s GDP in 2025 if every state matched the state with the fastest progress over the last 10 years in three areas: women’s participation in the workforce, the share of women’s jobs that are full-time, and the mix of sectors in which women work. That’s 10% higher than if no action is taken to narrow the U.S. gender gap, and it means that an economy the size of Texas could be added in less than a decade. These numbers don’t come close to the economic value of true equality between men and women — which would net the U.S. economy up to $4.3 trillion by 2025.