As i know, there are two ways to calculate MySQL database size.

1. SQL script

Sum up the data_length + index_length is equal to the total table size.

  1. data_length – store the real data.
  2. index_length – store the table index.

Here’s the SQL script to list out the entire databases size

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 ;

Another SQL script to list out one database size, and each tables size in detail

SELECT TABLE_NAME, table_rows, data_length, index_length, 
round(((data_length + index_length) / 1024 / 1024),2) "Size in MB"
FROM information_schema.TABLES WHERE table_schema = "schema_name";

2. Locate the MySQL stored data

Access this article to find out where does MySQL database saved the data.

Windows
Locate the MySQL ibdata1 file, right click on the file and click the properties, see the size? :)

Linux
Locate the MySQL ibdata1 file

mkyong@myserver:/var/lib/mysql$ ls -lh
total 1.5G
drwx------ 2 mysql mysql 4.0K 2009-08-26 13:36 mydatabase
-rw-r--r-- 1 root  root     0 2009-08-19 09:39 debian-5.0.flag
-rw-rw---- 1 mysql mysql 1.5G 2009-08-27 17:32 ibdata1
-rw-rw---- 1 mysql mysql 5.0M 2009-08-27 17:32 ib_logfile0
-rw-rw---- 1 mysql mysql 5.0M 2009-08-27 17:32 ib_logfile1
drwxr-xr-x 2 mysql root  4.0K 2009-08-19 11:19 mysql
-rw------- 1 root  root     6 2009-08-19 09:39 mysql_upgrade_info
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