As you can tell these are my messed up functions that convert dates into seconds and vice-versa. They're a little disorganised but they're the ones I copy and paste to my scripts then modify.

In it's straightforward form
FormatTime( TimeString, Format )
{
     FormatTime, FormattedTime , TimeString, %Format% 
     return Formattedtime
}


The following function is to convert a given SQL date or a European date formatted value: 
    	FormatDate(val)
    	{
    		; SQL format (yyyy-mm-dd HH:mm:ss)
    		IfInString, val, -
    		{
    			StringReplace, val, val, -,,All
    			StringReplace, val, val, :,,All
    			StringReplace, val, val, %A_Space%,,All
    		}
    		; Standard European format (dd/mm/yyyy HH:mm:ss)
    		IfInString, val, /
    		{
    			ThisTime:=SubStr(val, InStr(val, " ")+1)
    			StringReplace, ThisTime, ThisTime, :,,A
    			ThisTime=%ThisTime%
    			ThisDate:=SubStr(val, 1, InStr(val, " "))
    			ThisDate=%ThisDate%
    			ThisDate:=SubStr(ThisDate, 7) . SubStr(ThisDate, 4, 2) . SubStr(ThisDate, 1, 2)
    			ThisDate=%ThisDate%
    			val=%ThisDate%%ThisTime%
    		}
    		FormatTime, val, %val%, ddd dd-MMM-yyyy HH:mm:ss
    		Return val
    	}


    	// returns format Sat 01-Jan-2011 01:00:00

The next function usually accompanies the above one. It will basically convert seconds into days, hours, minutes, etc.: 
    	FormatSeconds(val)
    	{
    		IfInString, val, -
    		{
    			Month:=SubStr(val, 8, 3)
    			Month:=Month * 1
    			Months=Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec
    			StringSplit, MonthNameArray, Months, |
    			Month:=MonthNameArray%Month%
    			TimeString1:=SubStr(val, 12, 4)
    			TimeString1=%TimeString1%%Month%
    			TimeString1:=TimeString1 . SubStr(val, 5, 2) . SubStr(val, 17, 2) . SubStr(val, 20, 2) . SubStr(val, 23, 2)
    			TimeString2:=A_Now
    			EnvSub, TimeString2, %TimeString1%, Seconds
    			val:=TimeString2
    		}

    		strVal=
    		ThisDays:=val / 86400
    		IfInString, ThisDays, .
    			ThisDays:=SubStr(ThisDays, 1, InStr(ThisDays, ".")-1)
    		ThisHours:=(Mod(val, 86400)/3600)
    		IfInString, ThisHours, .
    			ThisHours:=SubStr(ThisHours, 1, InStr(ThisHours, ".")-1)
    		ThisMins:=(Mod(val, 3600)/60)
    		IfInString, ThisMins, .
    			ThisMins:=SubStr(ThisMins, 1, InStr(ThisMins, ".")-1)
    		ThisSecs:=Mod(val, 60)
    		IfInString, ThisSecs, .
    			ThisSecs:=SubStr(ThisSecs, 1, InStr(ThisSecs, ".")-1)
    		If ThisDays>0
    		{
    			If ThisDays>365
    			{
    				ThisYears:=ThisDays/365
    				IfInString, ThisYears, .
    					ThisYears:=SubStr(ThisYears, 1, InStr(ThisYears, ".")-1)

                    Grammar:=(ThisYears=1) ? "" : "s"
    				strVal=%ThisYears% year%Grammar%,
    				ThisDays:=ThisDays - (ThisYears*365)
                    Grammar:=(ThisDays=1) ? "" : "s"
    				strVal=%strVal% %ThisDays% day%Grammar%,
    			} else {
                    Grammar:=(ThisDays=1) ? "" : "s"
    				strVal=%ThisDays% day%Grammar%,
    			}
    		}
    		If ThisHours>0
    		{
                Grammar:=(ThisHours=1) ? "" : "s"
    			strVal=%strVal% %ThisHours% hour%Grammar%,
    		}
    		If ThisMins>0
    		{
                Grammar:=(ThisMins=1) ? "" : "s"
    			strVal=%strVal% %ThisMins% minute%Grammar%,
    		}
            Grammar:=(ThisSecs=1) ? "" : "s"
    		strVal=%strVal% %ThisSecs% second%Grammar%
    		Return strVal
    	}