Calendar-based suggestion of travel options involves suggesting a travel option based on events stored in a calendar of a user. For example, a user in San Francisco may be scheduled for a business trip to New York, and the user's calendar may show a dinner reservation in San Francisco on Saturday, September 3 and business meeting in New York on Monday, September 5. A suggestion machine accesses calendar data of the user and travel data for several available travel options (e.g., flights from San Francisco to New York). Based on the accessed calendar data and travel data, the suggestion machine determines that one or more travel options (e.g., a flight on Sunday, September 4) are compatible with the dinner reservation and the business meeting on the user's calendar. The suggestion machine presents these compatible travel options to the user.