Formatting DateTime values

Azure Storage DateTime values must be represented as combined Coordinated Universal Time (UTC) values. UTC formats are described by ISO 8601.

Accepted ISO 8601 UTC formats

The following ISO 8601 UTC formats are currently accepted by Azure Storage. The date value is required, while the time value is optional:

  • YYYY-MM-DDThh:mm<TZDSuffix>
  • YYYY-MM-DDThh:mm:ss<TZDSuffix>

For the date value in these formats, YYYY is a four-digit year representation, MM is a two-digit month representation starting at 1, and DD is a two-digit day representation starting at 1.

If the optional time value is included, a literal designator T is required to separate the time value from the date value. For the time value, hh is the hour representation in 24-hour notation, mm is the two-digit minute representation, and ss is the two-digit second representation. Each of these values is expressed as an integer, starting at zero.

If the time value includes seconds, it may optionally also include up to 7 decimal digits of fractional seconds, following the pattern hh:mm:ss[.f{1,7}]. This pattern is supported by the Azure Storage APIs, tools, and client libraries. You must use a period rather than commas to delineate the fractional seconds value.

If you include the optional time zone suffix <TZDSuffix>, it must be expressed as either:

  • A literal value Z, designating that the time value is expressed as UTC time; or
  • An offset indicating the time bias from UTC time. The offset requires a leading + for a positive offset and leading - for a negative offset. The value of the offset must fall between -23:59 and +23:59.

An example of the combined UTC format is shown below. The date is specified first, followed by the literal value T, which designates the beginning of the time element. The literal value Z at the end of the string indicates that the time is expressed in UTC.

The date/time value for November 16, 2020 at 4:25:03 AM in UTC time is expressed as:


To express the same time in Eastern Standard Time (EST), which is five hours earlier that UTC, add the offset to the value:


See also

Azure Storage REST API reference