Get sizes of all databases in phpMyAdmin

If you logged in as root account you'll be able to see the default information_schema database, and the data was included in "TABLES" table.

In order to more readable stats, you can run the following command, this will output the formatted result:

SELECT table_schema "Data Base Name",
sum( data_length + index_length ) / 1024 / 1024 "Data Base Size in MB"
FROM information_schema.TABLES GROUP BY table_schema;

source:

http://www.uponmyshoulder.com/blog/2010/get-database-size-in-phpmyadmin/