Estimate Database Backup and Restore Progress

SELECT r.session_id AS [Session_Id]
	,r.command AS [command]
	,CONVERT(NUMERIC(6, 2), r.percent_complete) AS [% Complete]
	,GETDATE() AS [Current Time]
	,CONVERT(VARCHAR(20), DATEADD(ms, r.estimated_completion_time, GetDate()), 20) AS [Estimated Completion Time]
	,CONVERT(NUMERIC(32, 2), r.total_elapsed_time / 1000.0 / 60.0) AS [Elapsed Min]
	,CONVERT(NUMERIC(32, 2), r.estimated_completion_time / 1000.0 / 60.0) AS [Estimated Min]
	,CONVERT(NUMERIC(32, 2), r.estimated_completion_time / 1000.0 / 60.0 / 60.0) AS [Estimated Hours]
	,CONVERT(VARCHAR(1000), (
			SELECT SUBSTRING(TEXT, r.statement_start_offset / 2, CASE 
						WHEN r.statement_end_offset = - 1
							THEN 1000
						ELSE (r.statement_end_offset - r.statement_start_offset) / 2
						END) 'Statement text'
			FROM sys.dm_exec_sql_text(sql_handle)
			))
FROM sys.dm_exec_requests r
WHERE command like 'RESTORE%'
or	command like 'BACKUP%'

SELECT
session_id,
start_time,
status,
command,
percent_complete,
estimated_completion_time,
estimated_completion_time /60/1000 as estimate_completion_minutes,
--(select convert(varchar(5),getdate(),8)),
DATEADD(n,(estimated_completion_time /60/1000),GETDATE()) as estimated_completion_time
FROM    sys.dm_exec_requests where command = 'BACKUP DATABASE' OR command = 'RESTORE DATABASE'

Sources:

How to Get Status of Running Backup and Restore in SQL Server? – Interview Question of the Week #113