Evaluating the economic impact of “social distancing” measures taken to arrest the spread of COVID-19 raises a number of fundamental questions about the modern economy: How many jobs can be performed at home? What share of total wages are paid to such jobs? How does the scope for working from home vary across cities or industries? To answer these questions, we classify the feasibility of working at home for all occupations and merge this classification with occupational employment counts for the United States. Our classification implies that 37 percent of U.S. jobs can plausibly be performed at home. We obtain our estimate by identifying job characteristics that clearly rule out the possibility of working entirely from home, neglecting many characteristics that would make working from home difficult.