ISO 8601 Data elements and interchange formats – Information interchange – Representation of dates and times is an international standard covering the exchange of date and time-related data. It was issued by the International Organization for Standardization (ISO) and was first published in 1988. The purpose of this standard is to provide an unambiguous and well-defined method of representing dates and times, so as to avoid misinterpretation of numeric representations of dates and times, particularly when data is transferred between countries with different conventions for writing numeric dates and times.

The standard organizes the data so the largest temporal term (the year) appears first in the data string and progresses to the smallest term (the second). It also provides for a standardized method of communicating time-based information across time zones by attaching an offset to Coordinated Universal Time (UTC).^[1]

History[link]

The first edition of the ISO 8601 standard was published in 1988. It unified and replaced a number of older ISO standards on various aspects of date and time notation: ISO 2014, ISO 2015, ISO 2711, ISO 3307, and ISO 4031.^[2] It has been superseded by a second edition in 2000 and by the current third edition published on 3 December 2004.

ISO 2014 was the standard that originally introduced the big-endian all-numeric date notation [YYYY]-[MM]-[DD]. The ISO week numbering system was introduced in ISO 2015, and the identification of days by ordinal dates was originally defined in ISO 2711.

It is maintained by ISO Technical Committee TC 154.^[3]

General principles[link]

• Date and time values are organized from the most to the least significant: year, month (or week), day, hour, minute, second, and fraction of second. The lexicographical order of the representation thus corresponds to chronological order, except for date representations involving negative years. This allows dates to be naturally sorted by, for example, file systems.
• Each date and time value has a fixed number of digits that must be padded with leading zeros.
• Representations can be done in one of two formats—a basic format with a minimal number of separators or an extended format with separators added to enhance human readability.^[1] The standard notes^[4] that "The basic format should be avoided in plain text." The separator used between date values (year, month, week, and day) is the hyphen, while the colon is used as the separator between time values (hours, minutes, and seconds). For example, the 6th day of the 1st month of the year 2009 may be written as "2009-01-06" in the extended format or simply as "20090106" in the basic format without ambiguity.
• For reduced precision,^[5] any number of values may be dropped from any of the date and time representations, but in the order from the least to the most significant. For example, "2004-05" is a valid ISO 8601 date, which indicates May (the fifth month) 2004. This format will never represent the 5th day of an unspecified month in 2004, nor will it represent a time-span extending from 2004 into 2005.
• If necessary for a particular application, the standard supports the addition of a decimal fraction to the smallest time value in the representation.

Dates[link]

The standard uses the Gregorian calendar, which serves as an international standard for civil use.^[6]

ISO 8601 fixes a reference calendar date to the Gregorian calendar of 20 May 1875 as the date the Convention du Mètre (Metre Convention) was signed in Paris. However, ISO calendar dates before the Convention are still compatible with the Gregorian calendar all the way back to the official introduction of the Gregorian calendar on 1582-10-15. Earlier dates, in the proleptic Gregorian calendar, may be used by mutual agreement of the partners exchanging information. The standard states that every date must be consecutive, so usage of the Julian calendar would be contrary to the standard (because at the switchover date, the dates would not be consecutive).

Years[link]

ISO 8601 prescribes, as a minimum, a four-digit year [YYYY] to avoid the year 2000 problem. It therefore represents years from 0000 to 9999, year 0000 being equal to 1 BC and all others AD.

To represent years before 0000 or after 9999, the standard also permits the expansion of the year representation but only by prior agreement between the sender and the receiver.^[7]

An expanded year representation [±YYYYY] must have an agreed-upon number of extra year digits beyond the four-digit minimum, and it should always be prefixed with a + or − sign instead of the common AD/CE or BC/BCE notation; by convention year zero is labelled positive: +0000. Note the addition of a year zero causes earlier years to be different by one when converted; for example, the year 3 BC would be denoted by −0002.^[8]

Calendar dates[link]

Calendar date representations are in the form as shown in the box to the right. [YYYY] indicates a four-digit year, 0000 through 9999. [MM] indicates a two-digit month of the year, 01 through 12. [DD] indicates a two-digit day of that month, 01 through 31. For example, "the 5th of April 1981" may be represented as either "1981-04-05" in the extended format or "19810405" in the basic format.

The standard also allows for calendar dates to be written with reduced precision. For example, one may write "1981-04" to mean "1981 April", and one may simply write "1981" to refer to that year or "19" to refer to the century from 1900 to 1999 inclusive.

Although the standard allows both the YYYY-MM-DD and YYYYMMDD formats for complete calendar date representations, if the day [DD] is omitted then only the YYYY-MM format is allowed. By disallowing dates of the form YYYYMM, the standard avoids confusion with the truncated representation YYMMDD (still often used).

Week dates[link]

Week date representations are in the format as shown in the box to the right. [YYYY] indicates the ISO week-numbering year which is slightly different from the calendar year (see below). [Www] is the week number prefixed by the letter 'W', from W01 through W53. [D] is the weekday number, from 1 through 7, beginning with Monday and ending with Sunday. This form is popular in the manufacturing industries.

There are mutually equivalent descriptions of week 01:

• the week with the year's first Thursday in it (the formal ISO definition),
• the week with 4 January in it,
• the first week with the majority (four or more) of its days in the starting year, and
• the week starting with the Monday in the period 29 December – 4 January.

If 1 January is on a Monday, Tuesday, Wednesday or Thursday, it is in week 01. If 1 January is on a Friday, Saturday or Sunday, it is in week 52 or 53 of the previous year (there is no week 00). 28 December is always in the last week of its year.

The week number can be described by counting the Thursdays: week 12 contains the 12th Thursday of the year.

The ISO week-numbering year starts at the first day (Monday) of week 01 and ends at the Sunday before the new ISO year (hence without overlap or gap). It consists of 52 or 53 full weeks. The ISO week-numbering year number deviates from the number of the calendar year (Gregorian year) on a Friday, Saturday, and Sunday, or a Saturday and Sunday, or just a Sunday, at the start of the calendar year (which are at the end of the previous ISO week-numbering year) and a Monday, Tuesday and Wednesday, or a Monday and Tuesday, or just a Monday, at the end of the calendar year (which are in week 01 of the next ISO week-numbering year). For Thursdays, the ISO week-numbering year number is always equal to the calendar year number.

Examples:

• Monday 29 December 2008 is written "2009-W01-1"
• Sunday 3 January 2010 is written "2009-W53-7"

For an overview of week numbering systems see week number. The US system has weeks from Sunday through Saturday, and partial weeks at the beginning and the end of the year. An advantage is that no separate year numbering like the ISO week-numbering year is needed, while correspondence of lexicographical order and chronological order is preserved.

Ordinal dates[link]

An ordinal date is a simple form for occasions when the arbitrary nature of week and month definitions are more of an impediment than an aid, for instance, when comparing dates from different calendars. As represented above, [YYYY] indicates a year. [DDD] is the day of that year, from 001 through 365 (366 in leap years). For example, "1981-04-05" is also "1981-095".

This format is used with simple hardware systems that have a need for a date system, but where including full calendar calculation software may be a significant nuisance. This system is sometimes incorrectly referred to as "Julian Date", whereas the astronomical Julian Date is a sequential count of the number of days since day 0 beginning 1 January 4713 BC Greenwich noon, Julian proleptic calendar (or noon on ISO date -4713-11-24 which uses the Gregorian proleptic calendar with a year [0000]).

Times[link]

ISO 8601 uses the 24-hour clock system. The basic format is [hh][mm][ss] and the extended format is [hh]:[mm]:[ss].

• [hh] refers to a zero-padded hour between 00 and 24 (where 24 is only used to notate midnight at the end of a calendar day).
• [mm] refers to a zero-padded minute between 00 and 59.
• [ss] refers to a zero-padded second between 00 and 60 (where 60 is only used to notate an added leap second).

So a time might appear as either "134730" in the basic format or "13:47:30" in the extended format.

It is also acceptable to omit lower order time elements for reduced accuracy:^[5] [hh]:[mm], [hh][mm] and [hh] are all used.

Midnight is a special case and can be referred to as both "00:00" and "24:00". The notation "00:00" is used at the beginning of a calendar day and is the more frequently used. At the end of a day use "24:00". Note that "2007-04-05T24:00" is the same instant as "2007-04-06T00:00" (see Combined date and time representations below).

Decimal fractions may also be added to any of the three time elements. A decimal mark, either a comma or a dot (without any preference as stated in resolution 10 of the 22nd General Conference CGPM in 2003^[9], but with a preference for a comma according to ISO 8601:2004^[10]), is used as a separator between the time element and its fraction. A fraction may only be added to the lowest order time element in the representation. To denote "14 hours, 30 and one half minutes", do not include a seconds figure. Represent it as "14:30,5", "1430,5", "14:30.5", or "1430.5". There is no limit on the number of decimal places for the decimal fraction. However, the number of decimal places needs to be agreed to by the communicating parties.

Time zone designators[link]

Time zones in ISO 8601 are represented as local time (with the location unspecified), as UTC, or as an offset from UTC.

If no UTC relation information is given with a time representation, the time is assumed to be in local time. While it may be safe to assume local time when communicating in the same time zone, it is ambiguous when used in communicating across different time zones. It is usually preferable to indicate a time zone (zone designator) using the standard’s notation.

UTC[link]

If the time is in UTC, add a 'Z' directly after the time without a space. 'Z' is the zone designator for the zero UTC offset. "09:30 UTC" is therefore represented as "09:30Z" or "0930Z". "14:45:15 UTC" would be "14:45:15Z" or "144515Z".

UTC time is also known as 'Zulu' time, since 'Zulu' is the NATO phonetic alphabet word for 'Z'.

Time offsets from UTC[link]

The offset from UTC is given in the format ±[hh]:[mm], ±[hh][mm], or ±[hh]. So if the time being described is one hour ahead of UTC (such as the time in Berlin during the winter), the zone designator would be "+01:00", "+0100", or simply "+01". This is appended to the time in the same way that 'Z' was above. The offset from UTC changes with daylight saving time, e.g. a time offset in Chicago, would be "-06:00" for the winter (Central Standard Time) and "-05:00" for the summer (Central Daylight Time).

The following times all refer to the same moment: "18:30Z", "22:30+04", "1130-0700", and "15:00-03:30". Nautical time zone letters are not used with the exception of Z. To calculate UTC time one has to subtract the offset from the local time, e.g. for "15:00-03:30" do 15:00 − (−03:30) to get 18:30 UTC.

The offset can also be used in the case where the UTC time is known, but the local offset is not. In this case the offset is "-00:00", which is semantically different from "Z" or "+00:00", as these imply that UTC is the preferred reference point for those times.^[11]

Combined date and time representations[link]

A single point in time can be represented by concatenating: a complete date expression, the letter T as a delimiter, and a valid time expression. For example "2007-04-05T14:30".

Either basic or extended formats may be used, but both date and time must use the same format. The date expression may be calendar, week, or ordinal, and must use a complete representation. The time expression may use reduced accuracy. It is permitted to omit the 'T' character by mutual agreement.^[12]

Durations[link]

Durations are a component of time intervals and define the amount of intervening time in a time interval. They should only be used as part of a time interval as prescribed by the standard. Time intervals are discussed in the next section.

Durations are represented by the format P[n]Y[n]M[n]DT[n]H[n]M[n]S or P[n]W as shown to the right. In these representations, the [n] is replaced by the value for each of the date and time elements that follow the [n]. Leading zeros are not required, but the maximum number of digits for each element should be agreed to by the communicating parties. The capital letters P, Y, M, W, D, T, H, M, and S are designators for each of the date and time elements and are not replaced.

• P is the duration designator (historically called "period") placed at the start of the duration representation.
• Y is the year designator that follows the value for the number of years.
• M is the month designator that follows the value for the number of months.
• W is the week designator that follows the value for the number of weeks.
• D is the day designator that follows the value for the number of days.
• T is the time designator that precedes the time components of the representation.
• H is the hour designator that follows the value for the number of hours.
• M is the minute designator that follows the value for the number of minutes.
• S is the second designator that follows the value for the number of seconds.

For example, "P3Y6M4DT12H30M5S" represents a duration of "three years, six months, four days, twelve hours, thirty minutes, and five seconds". Date and time elements including their designator may be omitted if their value is zero, and lower order elements may also be omitted for reduced precision. For example, "P23DT23H" and "P4Y" are both acceptable duration representations.

To resolve ambiguity, "P1M" is a one-month duration and "PT1M" is a one-minute duration (note the time designator, T, that precedes the time value). The smallest value used may also have a decimal fraction, as in "P0.5Y" to indicate half a year. This decimal fraction may be specified with either a comma or a full stop, as in "P0,5Y" or "P0.5Y". The standard does not prohibit date and time values in a duration representation from exceeding their "carry-over points" except as noted below. Thus, "PT36H" could be used as well as "P1DT12H" for representing the same duration.

Alternatively, a format for duration based on combined date and time representations may be used by agreement between the communicating parties either in the basic format PYYYYMMDDThhmmss or in the extended format P[YYYY]-[MM]-[DD]T[hh]:[mm]:[ss]. For example, the first duration shown above would be "P0003-06-04T12:30:05". However, individual date and time values cannot exceed their moduli (e.g. a value of 13 for the month or 25 for the hour would not be permissible).

Time intervals[link]

A time interval is the intervening time between two time points. The amount of intervening time is expressed by a duration (as described in the previous section). The two time points (start and end) are expressed by either a combined date and time representation or just a date representation.

There are four ways to express a time interval:

1. Start and end, such as "2007-03-01T13:00:00Z/2008-05-11T15:30:00Z"
2. Start and duration, such as "2007-03-01T13:00:00Z/P1Y2M10DT2H30M"
3. Duration and end, such as "P1Y2M10DT2H30M/2008-05-11T15:30:00Z"
4. Duration only, such as "P1Y2M10DT2H30M", with additional context information

Of these, the first three require two values separated by an interval designator which is usually a solidus or forward slash "/". In certain applications, a double hyphen (--) can be used as a separator instead of a solidus (see Section 4.4.2 of the standard).

For <start>/<end> expressions, if any elements are missing from the end value, they are assumed to be the same as for the start value including the time zone. This feature of the standard allows for concise representations of time intervals. For example, the date of a two-hour meeting including the start and finish times could be simply shown as "2007-12-14T13:30/15:30", where "/15:30" implies "/2007-12-14T15:30" (the same date as the start), or the beginning and end dates of a monthly billing period as "2008-02-15/03-14", where "/03-14" implies "/2008-03-14" (the same year as the start).

If greater precision is desirable to represent the time interval, then more time elements can be added to the representation. An observation period that has a duration of approximately three days, for example, can be succinctly shown as "2007-11-13/15", i.e. from any time on 2007-11-13 to any time on 2007-11-15. If a more exact start and end of the observation period need to be shown either for clarity or for measurement and recording purposes, the same time interval representation could be expanded to "2007-11-13T00:00/15T24:00", i.e. midnight at the start (T00:00) of 2007-11-13 to midnight at the end (T24:00) of 2007-11-15, a total of 72 hours.

Repeating intervals[link]

Repeating intervals are specified in section "4.5 Recurring time interval". They are formed by adding "R[n]/" to the beginning of an interval expression, where 'R' is used as the letter itself and [n] is replaced by the number of repetitions. Leaving out the value for [n] means an unbounded number of repetitions. So, to repeat the interval of "P1Y2M10DT2H30M" five times starting at "2008-03-01T13:00:00Z", use "R5/2008-03-01T13:00:00Z/P1Y2M10DT2H30M".

Truncated representations[link]

ISO 8601:2000 allowed truncation (by agreement), where leading components of a date or time are omitted. Notably, this allowed two-digit years to be used and the ambiguous formats YY-MM-DD and YYMMDD. This provision was removed in ISO 8601:2004.

See also[link]

• Date and time representation by country
• ISO 8601 usage
• Astronomical year numbering

Notes[link]

External links[link]

• ISO's catalog entry for ISO 8601:2004
• Use international date format (ISO) - Quality Web Tips The World Wide Web Consortium (W3C)
• ISO 8601 at the Open Directory Project
• ISO 8601 summary by Markus Kuhn
• Summary of 8601 by ISO
• Technical Committee ISO/TC 154, Processes, data elements and documents in commerce, industry and administration.
• The Mathematics of the ISO 8601 Calendar
• W3C Specification about UTC Date and Time and IETF Internet standard RFC 3339, based on ISO 8601

This biographical article needs additional citations for verification. It includes attribution to IMDb, which may not be a reliable source for biographical information. Please help by adding additional, reliable sources for verification. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (April 2008)

John Powell
Background information
Born	(1963-09-18) 18 September 1963 (age 48)
Origin	London, England, United Kingdom
Genres	Film scores
Occupations	Composer, Conductor, Music producer
Instruments	Piano, Violin
Years active	1990-present

John Powell (born 18 September 1963) is an English composer, best known for his scores to motion pictures. He has been based in the United States since 1997 and has composed the scores to over fifty feature films. He rose to fame in the late 1990s and 2000s, scoring numerous animated films, in addition to his live-action collaborations with directors Doug Liman and Paul Greengrass. His 2010 score for the film How to Train Your Dragon earned him his first Academy Award nomination at the 83rd Academy Awards. He was a member of Hans Zimmer's music studio, Remote Control Productions, and collaborated frequently with other composers from the studio, including Harry Gregson-Williams and Zimmer himself.

Life and career[link]

Powell was born in London. He originally trained as a violinist as a child, before studying at London's Trinity College of Music. He later ventured into jazz and rock music, playing in a soul band the Fabulistics. On leaving college, he composed music for commercials, which led to a job as an assistant to the composer Patrick Doyle on several film productions, including Much Ado About Nothing.

In 1995, he co-founded the London-based commercial music house Independently Thinking Music, which produced scores for more than 100 British and French commercials and independent films.

Powell's first film score was for the 1990 film Stay Lucky. He moved to the U.S. in 1997, and scored his first major film, Antz in 1998, the first film produced by DreamWorks Animation which he co-scored with fellow British composer Harry Gregson-Williams. Two years later the two collaborated again to compose the score to Chicken Run, and again the following year on Shrek, which won the Academy Award for Best Animated Feature. All subsequent Shrek films however, have been scored solely by Gregson-Williams. During 2001 he also scored Evolution, I Am Sam, Just Visiting, and Rat Race.

In 2002 Powell was hired to score The Bourne Identity, after Carter Burwell left the project, and has gone on to score all of director Doug Liman's subsequent films. He also returned to score the other two films in the series; The Bourne Supremacy and The Bourne Ultimatum, which were both directed by British director Paul Greengrass.

Following the Bourne films, Powell collaborated with Liman again to score the 2005 film Mr. & Mrs. Smith. That year, he also scored Robots.

In 2006, he scored Greengrass' United 93. He also composed music for Ice Age: The Meltdown, following David Newman, who scored the first Ice Age film, as well as X-Men: The Last Stand, and Happy Feet, for which he won a Film & TV Music Award for Best Score for an Animated Feature Film. The following year he scored The Bourne Ultimatum. In 2008 he collaborated with composer Hans Zimmer to score Kung Fu Panda, and also wrote music that year for Jumper, Hancock, and Bolt. In 2009 he scored the third, and to date, most popular installment in the Ice Age series; Dawn of the Dinosaurs.

In 2010, Powell composed the score to How To Train Your Dragon. This was his sixth score for a DreamWorks Animation film, although the first where he composed the whole score himself. It also became his first work to be nominated for the Academy Award for Best Original Score. That year, he has also scored Greengrass' Green Zone, and Knight and Day.

Discography[link]

Awards and nominations[link]

Awards[link]

• 1998 ASCAP Award for Top Box Office Films - Face/Off
• 1999 ASCAP Award for Top Box Office Films - Antz (with Harry Gregson-Williams)
• 2001 ASCAP Award for Top Box Office Films - Chicken Run (with Harry Gregson-Williams)
• 2001 Annie Award for Outstanding Individual Achievement for Music Score an Animated Feature Production - Shrek (with Harry Gregson-Williams)
• 2002 ASCAP Award for Top Box Office Films - Shrek (with Harry Gregson-Williams)
• 2003 ASCAP Award for Top Box Office Films - The Bourne Identity
• 2004 ASCAP Award for Top Box Office Films - The Italian Job
• 2005 ASCAP Award for Top Box Office Films - The Bourne Supremacy
• 2006 ASCAP Award for Top Box Office Films - Mr. & Mrs. Smith
• 2006 ASCAP Award for Top Box Office Films - Robots
• 2009 Annie Award for Best Music in an Animated Feature Production - Kung Fu Panda (with Hans Zimmer)
• 2009 Annie Award for Best Music in an Animated Television Production or Short Form - Kung Fu Panda: Secrets of the Furious Five (with Henry Jackman and Hans Zimmer)
• 2011 Annie Award for Best Music in an Animated Feature Production - How To Train Your Dragon
• 2011 IFMCA Award for Best Original Score for an Animated Feature - How To Train Your Dragon
• 2011 IFMCA Award for Film Score of the Year - How To Train Your Dragon

Nominations[link]

• 1998 Saturn Award for Best Music - Face/Off
• 1999 Annie Award for Outstanding Individual Achievement for Music in an Animated Feature Production - Antz (with Harry Gregson-Williams)
• 2000 Annie Award for Outstanding Individual Achievement for Music in an Animated Feature Production - The Road to El Dorado (with Hans Zimmer, Elton John and Tim Rice)
• 2001 Saturn Award for Best Music - The Road to El Dorado (with Hans Zimmer)
• 2001 Phoenix Film Critics Society Awards for Best Original Score - Chicken Run (with Harry Gregson-Williams)
• 2002 BAFTA Anthony Asquith Award for Film Music - Shrek (with Harry Gregson-Williams)
• 2002 Saturn Award for Best Music - Shrek (with Harry Gregson-Williams)
• 2005 Golden Satellite Award for Best Original Score - Alfie (with David A. Stewart and Mick Jagger)
• 2007 Saturn Award for Best Music - X-Men: The Last Stand
• 2007 Annie Award for Best Music in an Animated Feature Production - Ice Age: The Meltdown
• 2007 BAFTA Anthony Asquith Award for Film Music - Happy Feet
• 2008 Grammy for Best Score Soundtrack Album for Motion Picture, Television or Other Visual Media - Happy Feet
• 2008 Satellite Award for Best Original Score - Horton Hears a Who!
• 2008 Saturn Award for Best Music - The Bourne Ultimatum
• 2009 Saturn Award for Best Music - Jumper
• 2009 Annie Award for Best Music in an Animated Feature Production - Horton Hears a Who!
• 2010 Annie Award for Music in a Feature Production - Ice Age: Dawn of the Dinosaurs
• 2011 Saturn Award for Best Music - How To Train Your Dragon
• 2011 BAFTA Award for Best Original Music - How To Train Your Dragon
• 2011 Academy Award for Best Original Score - How To Train Your Dragon

References[link]

External links[link]

• John Powell at the Internet Movie Database
• SoundtrackNet - John Powell Biography