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TimeZone.GetUtcOffset Method

Returns the Coordinated Universal Time (UTC) offset for the specified local time.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
public abstract TimeSpan GetUtcOffset(
	DateTime time
)

Parameters

time
Type: System.DateTime
A date and time value.

Return Value

Type: System.TimeSpan
The Coordinated Universal Time (UTC) offset from Time.

This method returns the offset, or difference, between the time parameter and Coordinated Universal Time (UTC). That is:

time = UTC + offset

The method interprets the time zone of time based on its Kind property. If the value of the Kind property is DateTimeKind.Local or DateTimeKind.Unspecified, the method returns the offset of the local time zone. If the value of the Kind property is DateTimeKind.Utc, the method returns an offset equal to TimeSpan.Zero.

If the local time zone observes daylight saving time, GetUtcOffset applies the current adjustment rule to time when determining the offset of the local time zone. That is, the offset returned by GetUtcOffset reflects whether time falls in the time zone's standard time or its daylight saving time.

NoteNote

   The GetUtcOffset method recognizes only the current daylight saving time adjustment rule for the local time zone. As a result, it is guaranteed to accurately return the UTC offset of a local time only during the period in which the latest adjustment rule is in effect. It may return inaccurate results if Time is a historic date and time value that was subject to a previous adjustment rule.

The GetUtcOffset method corresponds to the TimeZoneInfo.GetUtcOffset method. Whenever possible, use the TimeZoneInfo.GetUtcOffset method.

Because the date and time value represented by Time and this value's offset from UTC are not tightly coupled, a local or unspecified date and time value can return a different offset value when run on different computers or when run on the same computer under different time zones. If this behavior is undesirable, use a DateTimeOffset value instead. The DateTimeOffset data type tightly couples a date and time value with its offset from UTC.

The following example uses the GetUtcOffset method to return the Coordinated Universal Time (UTC) offset for several local times.


// Example of the TimeZone.ToLocalTime( DateTime ) and 
// TimeZone.GetUtcOffset( DateTime ) methods.
using System;

class UTCTimeDemo
{
    static void Main( )
    {
        const string headFmt = "{0,-20}{1,-20}{2,-12}{3}";

        // Get the local time zone and a base Coordinated Universal 
        // Time (UTC).
        TimeZone localZone = TimeZone.CurrentTimeZone;
        DateTime baseUTC = new DateTime( 2000, 1, 1 );

        Console.WriteLine( "This example of \n" +
            "   TimeZone.ToLocalTime( DateTime ) and\n" +
            "   TimeZone.GetUtcOffset( DateTime ) \ngenerates the " +
            "following output, which varies depending on the time " +
            "zone \nin which it is run. The example creates several " +
            "Coordinated Universal \nTimes (UTC), displays the " +
            "corresponding local times and UTC offsets, \nand shows " +
            "if the times occur in daylight saving time (DST)." );
        Console.WriteLine( "\nLocal time: {0}\n", 
            localZone.StandardName );

        Console.WriteLine( headFmt, "UTC", "Local Time", 
            " Offset", "DST?" );
        Console.WriteLine( headFmt, "---", "----------", 
            " ------", "----" );

        // Generate several UTC times.
        for( int loopX = 0; loopX <= 10; loopX++ )
        {
            // Calculate the local time and UTC offset.
            DateTime localTime = localZone.ToLocalTime( baseUTC );
            TimeSpan localOffset = 
                localZone.GetUtcOffset( localTime );

            Console.WriteLine( "{0,-20:yyyy-MM-dd HH:mm}" +
                "{1,-20:yyyy-MM-dd HH:mm}{2,-12}{3}", 
                baseUTC, localTime, localOffset, 
                localZone.IsDaylightSavingTime( localTime ) );

            // Advance to another UTC.
            baseUTC = baseUTC.AddDays( 155.55 );
        }
    } 
} 

/*
This example of
   TimeZone.ToLocalTime( DateTime ) and
   TimeZone.GetUtcOffset( DateTime )
generates the following output, which varies depending on the time zone
in which it is run. The example creates several Coordinated Universal
Times (UTC), displays the corresponding local times and UTC offsets,
and shows if the times occur in daylight saving time (DST).

Local time: Pacific Standard Time

UTC                 Local Time           Offset     DST?
---                 ----------           ------     ----
2000-01-01 00:00    1999-12-31 16:00    -08:00:00   False
2000-06-04 13:12    2000-06-04 06:12    -07:00:00   True
2000-11-07 02:24    2000-11-06 18:24    -08:00:00   False
2001-04-11 15:36    2001-04-11 08:36    -07:00:00   True
2001-09-14 04:48    2001-09-13 21:48    -07:00:00   True
2002-02-16 18:00    2002-02-16 10:00    -08:00:00   False
2002-07-22 07:12    2002-07-22 00:12    -07:00:00   True
2002-12-24 20:24    2002-12-24 12:24    -08:00:00   False
2003-05-29 09:36    2003-05-29 02:36    -07:00:00   True
2003-10-31 22:48    2003-10-31 14:48    -08:00:00   False
2004-04-04 12:00    2004-04-04 05:00    -07:00:00   True
*/ 


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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