Each time you purchase a topic, 16 partitions are added.

In addition to the default number of partitions, 16 partitions are added each time you purchase a topic. Assume that you have purchased an instance that has 50 topics, a maximum traffic volume of 20 MB/s, and 400 default partitions. After you purchase another 10 topics for this instance, 160 partitions are added to the instance. The total number of partitions increases to 560.