This paper evaluates indicators to analyse mixed activities, representing a combination of various facilities and services, in urban areas. Although mixed activities play an important role in urban planning projects, measuring themhas been problematic due to the lack of appropriate data and measurement approaches. In ecology, there are dozens of potential diversity indices, which have been deployed in recent land use studies to measure mixed activities. However, ecologists have highlighted that these indices are not always expressed inintuitive units. Recognizing the limitation of commonly used diversity indices, Hill numbers, which represent a mathematically unified family of diversity indices, are used. Taking advantage of new data sources such as Points of Interest (POIs) from OpenStreetMap, this study applied Hill numbers on POIs to measure mixed activities at a quarter level in Frankfurt. Results showed that Hill1 (exponential of Shannon) is an appropriate quantitative measure to describe the diversity of facilities and services by a single numerical value. However, it is difficult to explain which factor, namely evenness or richness,has a stronger impact on the index. To gain a more comprehensive picture of mixed activities we suggest to considering further indicators such as evenness and richness.