Housing prices in many countries are growing faster than incomes. Much of this affordability problem can be explained by regulatory barriers to new construction. This column calculates countries’ ‘building-height gaps’ – the difference between the total height of a country’s stock of tall buildings and what the total height would have been if building height regulations were relatively less stringent, based on parameters from a benchmark set of countries. These gaps are larger for richer countries and for residential buildings rather than for commercial buildings, and they correlate strongly with housing prices, sprawl, congestion, and pollution.