How to get the size of all tables in a SQL Server database

exec sp_MSForEachTable 'exec sp_spaceused [?]';

use Chinook;
GO
exec sp_spaceused 'album';
GO

-- name          rows                 reserved           data               index_size         unused
-- Album         347                  144 KB             24 KB              32 KB              88 KB

exec sp_MSForEachTable 'exec sp_spaceused [?]';
GO


-- name         rows                 reserved           data               index_size         unused

-- Album        347                  144 KB             24 KB              32 KB              88 KB
-- name         rows                 reserved           data               index_size         unused

-- Artist       275                  72 KB              16 KB              16 KB              40 KB
-- name         rows                 reserved           data               index_size         unused

-- Customer     59                   144 KB             16 KB              32 KB              96 KB
-- And more...

SELECT
    s.Name AS SchemaName,
    t.Name AS TableName,
    p.rows AS NumRows,
    CAST(ROUND((SUM(a.total_pages) / 128.00), 2) AS NUMERIC(36, 2)) AS Total_MB,
    CAST(ROUND((SUM(a.used_pages) / 128.00), 2) AS NUMERIC(36, 2)) AS Used_MB,
    CAST(ROUND((SUM(a.total_pages) - SUM(a.used_pages)) / 128.00, 2) AS NUMERIC(36, 2)) AS Unused_MB
FROM
    sys.tables t
    JOIN sys.indexes i ON t.OBJECT_ID = i.object_id
    JOIN sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
    JOIN sys.allocation_units a ON p.partition_id = a.container_id
    LEFT OUTER JOIN sys.schemas s ON t.schema_id = s.schema_id
WHERE
    t.name NOT LIKE 'dt%'
    AND t.is_ms_shipped = 0
    AND i.object_id > 255
GROUP BY
    t.Name, s.Name, p.Rows
ORDER BY
    Total_MB DESC, t.Name

SET NOCOUNT ON;

USE [master];
GO

IF object_id('tempdb..#TableSizes') IS NOT NULL
    DROP TABLE #TableSizes;

CREATE TABLE #TableSizes
(
    recid          int IDENTITY (1, 1),
    DatabaseName   sysname,
    SchemaName     varchar(128),
    TableName      varchar(128),
    NumRows        bigint,
    Total_MB       decimal(15,2),
    Used_MB        decimal(15,2),
    Unused_MB      decimal(15,2)
)

EXEC sp_MSforeachdb 'USE [?];
INSERT INTO #TableSizes (DatabaseName, TableName, SchemaName, NumRows, Total_MB, Used_MB, Unused_MB)
SELECT
    ''?'' as DatabaseName,
    s.Name AS SchemaName,
    t.NAME AS TableName,
    p.rows AS NumRows,
    CAST(ROUND((SUM(a.total_pages) / 128.00), 2) AS NUMERIC(36, 2)) AS Total_MB,
    CAST(ROUND((SUM(a.used_pages) / 128.00), 2) AS NUMERIC(36, 2)) AS Used_MB,
    CAST(ROUND((SUM(a.total_pages) - SUM(a.used_pages)) / 128.00, 2) AS NUMERIC(36, 2)) AS Unused_MB
FROM
    sys.tables t
    JOIN sys.indexes i ON t.OBJECT_ID = i.object_id
    JOIN sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
    JOIN sys.allocation_units a ON p.partition_id = a.container_id
    LEFT OUTER JOIN sys.schemas s ON t.schema_id = s.schema_id
WHERE
    t.name NOT LIKE ''dt%''
    AND t.is_ms_shipped = 0
    AND i.object_id > 255
GROUP BY
    t.Name, s.Name, p.Rows
ORDER BY
    Total_MB DESC, t.Name';

SELECT   DatabaseName, TableName, SchemaName, NumRows, Total_MB, Used_MB, Unused_MB
FROM     #TableSizes
ORDER BY DatabaseName, SchemaName, TableName;