# 対象期間
$startDate = [DateTime]"2017/01/01"
$endDate = [DateTime]"2017/09/01"
$dist = New-TimeSpan $startDate $endDate
結果
ps1
Days : 243
Hours : 0
Minutes : 0
Seconds : 0
Milliseconds : 0
Ticks : 209952000000000
TotalDays : 243
TotalHours : 5832
TotalMinutes : 349920
TotalSeconds : 20995200
TotalMilliseconds : 20995200000