The World Bank Human Capital Index (HCI) is based on the productivity gains of future workers from human capital accumulation. But in many developing countries, a sizeable fraction of people are not employed, or are in jobs in which they cannot fully use their skills and cognitive abilities to increase their productivity. The Utilization-adjusted Human Capital Indices (UHCIs) adjust the HCI for labor-market underutilization of human capital, based on fraction of the working age population that are employed, or are in the types of jobs where they might be better able to use their skills and abilities to increase their productivity ("better employment"). The UHCIs generalize the growth-based interpretation of the HCI: the inverse of a country's UHCI score represents long-run GDP per capita with complete human capital and complete utilization, relative to that under the status quo. The UHCIs are designed to complement the HCI, and not to replace it: they have different purposes, and the challenges of measuring utilization mean that the UHCIs should be interpreted with caution for policy analysis. Both utilization measures are available for more than 160 countries, and are roughly U-shaped in per capita income, suggesting human capital is particularly underutilized in middle-income countries. Human capital is also underutilized for women: while the HCI is roughly equal across boys and girls, female UHCIs are typically lower than those for males, driven by lower employment rates.