Listing 1: Query That Returns Tempdb's Size at Last Start
SELECT
	alt.filename
	,alt.name
	,alt.size * 8.0 / 1024.0 as originalsize_MB
	,files.size* 8.0 / 1024.0 as currentsize_MB
FROM
	master.dbo.sysaltfiles  alt INNER JOIN tempdb.dbo.sysfiles files ON
		alt.fileid = files.fileid
WHERE
	dbid = db_id('tempdb')