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Why GMT?
GMT and the other libraries
Helping fix Temporal
Core Rules
Install
API Reference
Overview
calendar
Overview
business
businessDaysBetween
mergeCalendars
nextBusinessDay
previousBusinessDay
rollDate
calculate
bucketRange
floorToZone
getFiscalPeriod
getIsoWeekDate
getOrdinalDate
getQuarter
hours
addOperatingTime
isOpenAt
nextCloseAt
nextOpenAt
operatingIntervals
operatingTimeBetween
recurringWindows
validate
isValidBusinessCalendar
isValidFiscalPattern
isValidRollConvention
isValidZoneBucketUnit
duration
Overview
calculate
absDuration
addDuration
durationAs
getDurationSign
getDurationUnit
negateDuration
subtractDuration
compareDurations
formatDuration
isValidDuration
normalizeDuration
parseDuration
instant
Overview
convert
classifyLocal
fromOffsetInstant
resolveLocal
toOffsetInstant
isValidUtcOffset
Unreleased
interval
Overview
calculate
clampInterval
intersectIntervals
mergeIntervals
splitIntervalAt
subtractIntervals
sumIntervals
compare
intervalContains
intervalsOverlap
isValidInterval
plain
Overview
calculate
addBusinessDays
addDate
addDateTime
addTime
clampDate
closestDateTo
cycleDate
cycleDateTime
cycleTime
diffDate
diffDateAsDuration
diffDateTime
diffDateTimeAsDuration
diffTime
endOfDate
endOfDateTime
endOfQuarterForDate
endOfQuarterForDateTime
endOfTime
getDayOfYear
getDaysInMonth
getDaysInYear
getLargestDateDurationUnit
getLargestDateTimeDurationUnit
getLargestTimeDurationUnit
getLocaleDayOfWeek
getLocaleEndOfWeek
getLocaleStartOfWeek
getLocaleWeekYear
getQuarterForDate
getQuarterForDateTime
getWeekNumber
getWeekOfMonth
getWeeksInLocaleWeekYear
getWeeksInMonth
getWeeksInYear
getWeekYear
maxDate
maxDateTime
maxTime
minDate
minDateTime
minTime
nextWeekday
previousWeekday
roundDate
roundDateTime
roundTime
setDate
setDateTime
setTime
sortDates
sortDateTimes
sortTimes
startOfDate
startOfDateTime
startOfQuarterForDate
startOfQuarterForDateTime
startOfTime
subtractBusinessDays
subtractDate
subtractDateTime
subtractTime
weekOfYearForDate
weekOfYearForDateTime
chop
chopDate
chopMilliseconds
chopSeconds
chopTime
compare
areDatesEqual
areDatesEqualBy
areDateTimesEqual
areDateTimesEqualBy
areTimesEqual
isAfterDate
isAfterDateTime
isAfterTime
isBeforeDate
isBeforeDateTime
isBeforeTime
isBetweenDate
isBetweenDateTime
isBetweenTime
isBusinessDay
isFuture
isPast
isRelativeDay
isThisUnit
isWeekend
format
formatCalendar
formatDate
formatDateRange
formatDateTime
formatDateTimeRange
formatDateTimeToParts
formatDateToParts
formatRelativeDate
formatRelativeDateTime
formatRelativeTime
formatSqlDateTime
Unreleased
formatTime
get
getDay
getDayOfWeek
getHour
getMicrosecond
getMillisecond
getMinute
getMonth
getNanosecond
getNow
getNowUnit
getSecond
getToday
getWeekOfYear
getYear
interval
intervalAbutsDate
intervalAbutsDateTime
intervalAbutsTime
intervalContainsDate
intervalContainsDateTime
intervalContainsTime
intervalCountDate
intervalCountDateTime
intervalCountTime
intervalDifferenceDate
intervalDifferenceDateTime
intervalDifferenceTime
intervalDivideEquallyDate
intervalDivideEquallyDateTime
intervalDivideEquallyTime
intervalEngulfsDate
intervalEngulfsDateTime
intervalEngulfsTime
intervalFromDurationDate
intervalFromDurationDateTime
intervalFromDurationTime
intervalIntersectionDate
intervalIntersectionDateTime
intervalIntersectionTime
intervalLengthDate
intervalLengthDateTime
intervalLengthTime
intervalOverlappingDaysDate
intervalOverlappingDaysDateTime
intervalsOverlapDate
intervalsOverlapDateTime
intervalsOverlapTime
intervalSplitAtDate
intervalSplitAtDateTime
intervalSplitAtTime
intervalUnionDate
intervalUnionDateTime
intervalUnionTime
intervalXorAllDate
intervalXorAllDateTime
intervalXorAllTime
intervalXorDate
intervalXorDateTime
intervalXorTime
isValidDateInterval
isValidDateTimeInterval
isValidTimeInterval
mergeIntervalsDate
mergeIntervalsDateTime
mergeIntervalsTime
splitIntervalByUnitDate
splitIntervalByUnitDateTime
splitIntervalByUnitTime
locale
getLocaleEraNames
getLocaleMeridiems
getLocaleMonthNames
getLocaleWeekdayNames
map
mapDatesInRange
mapDaysInMonth
parse
parseDateTimeWithPattern
parseDateWithPattern
parseDayFromDate
parseDayFromDateTime
parseDayOfWeekFromDate
parseDayOfWeekFromDateTime
parseHourFromDateTime
parseHourFromTime
parseMicrosecondFromDateTime
parseMicrosecondFromTime
parseMillisecondFromDateTime
parseMillisecondFromTime
parseMinuteFromDateTime
parseMinuteFromTime
parseMonthFromDate
parseMonthFromDateTime
parseNanosecondFromDateTime
parseNanosecondFromTime
parseSecondFromDateTime
parseSecondFromTime
parseSqlDateTime
Unreleased
parseTimeWithPattern
parseUnitFromDate
parseUnitFromDateTime
parseUnitFromTime
parseWeekFromDate
parseWeekFromDateTime
parseYearFromDate
parseYearFromDateTime
validate
isLeapSecond
isLeapYear
isValidCalendarDate
isValidDate
isValidDateCycleField
isValidDateDurationUnit
isValidDateRange
isValidDateTime
isValidDateTimeCycleField
isValidDateTimeDurationUnit
isValidDateTimeRange
isValidDateTimeUnit
isValidDateUnit
isValidIsoDateLike
isValidSqlDateTime
Unreleased
isValidTime
isValidTimeCycleField
isValidTimeDurationUnit
isValidTimeRange
isValidTimeUnit
convertDateToCalendar
precision
Overview
convert
fromDotNetTicks
fromExcelSerial
fromFileTime
fromNanoseconds
fromNtpTimestamp
fromPgMicroseconds
toDotNetTicks
toExcelSerial
toFileTime
toNanoseconds
toNtpTimestamp
toPgMicroseconds
validate
isValidInstant
isValidNanoPattern
isValidNanoseconds
formatNanoseconds
parseNanoseconds
truncateNanoseconds
regex
Overview
date
day
month
plainDate
year
epcis
Unreleased
epcisEventTime
Unreleased
epcisTimeZoneOffset
Unreleased
leap-second
instantLeapSecond
leapSecond
time
fractionalSecond
hour
millisecond
minute
plainTime
second
unix
unixMilliseconds
unixSeconds
calendarDate
calendarZonedDateTime
httpDate
nanosecondDecimal
plainDateTime
rfc2822DateTime
rfc3339DateTime
sqlDateTime
timeZoneLike
utcDateTime
utcOffset
span
Overview
calculate
spanMs
spanNs
spanWallClock
isValidSpan
types
Overview
BusinessCalendar
CalendarOptions
CalendarSystem
CutoffOptions
DateCycleField
DateDurationUnit
DateTimeCycleField
DateTimeDurationUnit
DateTimeFormatOptions
DateTimeUnit
DateUnit
Disambiguation
DurationRelativeTo
DurationStringOptions
EdiDatePeriod
Unreleased
EdiDateTimePeriod
Unreleased
EdifactDateFormat
Unreleased
EdifactDatePeriodFormat
Unreleased
EdifactDateTimeFormat
Unreleased
EdifactDateTimePeriodFormat
Unreleased
EdifactOffsetDateTimeFormat
Unreleased
EdifactTimeFormat
Unreleased
EpcisEventTime
Unreleased
ExcelDateSystem
FiscalPattern
FractionalDigit
FreeTimeBasis
FreeTimeFirstDay
FreeTimeOptions
Interval
IsoWeekday
Leg
LocaleNameStyle
LocalWindow
Offset
OffsetInstant
OperatingOverride
OperatingSchedule
Overflow
PunctualityTolerance
RelativeRoundingMethod
RelativeTimeFormatOptions
RelativeUnit
RollConvention
RoundingOptions
ScheduleDeliveryOptions
TimeCycleField
TimeDurationUnit
TimestampClass
TimestampEvent
TwoDigitYearOptions
Unreleased
UnixUnit
X12DateFormat
Unreleased
X12DateRangeFormat
Unreleased
X12DateTimeFormat
Unreleased
X12DateTimeRangeFormat
Unreleased
X12OffsetTimeCode
Unreleased
X12TimeFormat
Unreleased
X12ZoneTimeCode
Unreleased
ZoneBucketUnit
unix
Overview
calculate
addUnix
diffUnix
diffUnixAsDuration
endOfQuarterForUnix
endOfUnix
isBetweenUnix
maxUnix
minUnix
roundUnix
setUnix
sortUnix
startOfQuarterForUnix
startOfUnix
subtractUnix
compare
areUnixEqual
areUnixEqualBy
isAfterUnix
isBeforeUnix
convert
convertUnixToPlainDate
convertUnixToPlainDateTime
convertUnixToPlainTime
convertUnixToUtc
convertUnixToZoned
format
formatCalendarUnix
formatRelativeUnix
formatUnix
get
getUnixDay
getUnixHour
getUnixMicrosecond
getUnixMillisecond
getUnixMinute
getUnixMonth
getUnixNanosecond
getUnixNow
getUnixNowUnit
getUnixSecond
getUnixYear
interval
intervalAbutsUnix
intervalContainsUnix
intervalCountUnix
intervalDifferenceUnix
intervalDivideEquallyUnix
intervalEngulfsUnix
intervalFromDurationUnix
intervalIntersectionUnix
intervalLengthUnix
intervalOverlappingDaysUnix
intervalsOverlapUnix
intervalSplitAtUnix
intervalUnionUnix
intervalXorAllUnix
intervalXorUnix
isValidUnixInterval
mergeIntervalsUnix
splitIntervalByUnitUnix
parse
parseDateFromUnix
parseDayFromUnix
parseDayOfWeekFromUnix
parseHourFromUnix
parseMicrosecondFromUnix
parseMillisecondFromUnix
parseMinuteFromUnix
parseMonthFromUnix
parseNanosecondFromUnix
parseSecondFromUnix
parseTimeFromUnix
parseUnitFromUnix
parseWeekFromUnix
parseYearFromUnix
validate
isValidUnixMilliseconds
isValidUnixRange
isValidUnixSeconds
isValidUnixUnit
utc
Overview
calculate
addUtc
diffUtc
diffUtcAsDuration
endOfQuarterForUtc
endOfUtc
isBetweenUtc
maxUtc
minUtc
roundUtc
setUtc
sortUtc
startOfQuarterForUtc
startOfUtc
subtractUtc
compare
areUtcEqual
areUtcEqualBy
isAfterUtc
isBeforeUtc
convert
convertUtcToPlainDate
convertUtcToPlainDateTime
convertUtcToPlainTime
convertUtcToUnix
convertUtcToZoned
format
formatCalendarUtc
formatHttpDate
Unreleased
formatRelativeUtc
formatUtc
get
getUtcDay
getUtcHour
getUtcMicrosecond
getUtcMillisecond
getUtcMinute
getUtcMonth
getUtcNanosecond
getUtcNow
getUtcNowUnit
getUtcSecond
getUtcYear
interval
intervalAbutsUtc
intervalContainsUtc
intervalCountUtc
intervalDifferenceUtc
intervalDivideEquallyUtc
intervalEngulfsUtc
intervalFromDurationUtc
intervalIntersectionUtc
intervalLengthUtc
intervalOverlappingDaysUtc
intervalsOverlapUtc
intervalSplitAtUtc
intervalUnionUtc
intervalXorAllUtc
intervalXorUtc
isValidUtcInterval
mergeIntervalsUtc
splitIntervalByUnitUtc
parse
parseDateFromUtc
parseDayFromUtc
parseDayOfWeekFromUtc
parseHourFromUtc
parseHttpDate
Unreleased
parseMicrosecondFromUtc
parseMillisecondFromUtc
parseMinuteFromUtc
parseMonthFromUtc
parseNanosecondFromUtc
parseSecondFromUtc
parseTimeFromUtc
parseUnitFromUtc
parseWeekFromUtc
parseYearFromUtc
validate
isValidHttpDate
Unreleased
isValidUtc
isValidUtcRange
isValidUtcTimestamp
Unreleased
chopUtc
zoned
Overview
calculate
addZoned
addZonedBusinessDays
clampZoned
closestZonedTo
cycleZoned
diffZoned
diffZonedAsDuration
endOfQuarterForZoned
endOfZoned
getHoursInZonedDay
getLocaleZonedDayOfWeek
getLocaleZonedEndOfWeek
getLocaleZonedStartOfWeek
getQuarterForZoned
maxZoned
minZoned
roundZoned
setZoned
sortZoned
startOfQuarterForZoned
startOfZoned
subtractZoned
subtractZonedBusinessDays
chop
chopZonedDate
chopZonedDateTime
chopZonedMilliseconds
chopZonedSeconds
chopZonedTime
chopZonedTimezone
compare
areZonedEqual
areZonedEqualBy
isAfterZoned
isBeforeZoned
isBetweenZoned
isInDaylightSaving
isZonedBusinessDay
isZonedFuture
isZonedPast
isZonedRelativeDay
isZonedThisUnit
isZonedWeekend
convert
convertPlainDateTimeToZoned
convertZonedToCalendar
convertZonedToPlainDateTime
convertZonedToUnix
convertZonedToUtc
convertZonedToZoned
format
formatCalendarZoned
formatRelativeZoned
formatRfc2822
formatRfc3339
formatTimeZoneName
formatZonedDateTime
formatZonedRange
formatZonedToParts
get
getDstTransitions
getSystemTimeZone
getTimeZoneOffset
getTimeZones
getZonedDay
getZonedDayOfWeek
getZonedHour
getZonedMicrosecond
getZonedMillisecond
getZonedMinute
getZonedMonth
getZonedNanosecond
getZonedNow
getZonedNowUnit
getZonedSecond
getZonedToday
getZonedWeekOfYear
getZonedYear
interval
intervalAbutsZoned
intervalContainsZoned
intervalCountZoned
intervalDifferenceZoned
intervalDivideEquallyZoned
intervalEngulfsZoned
intervalFromDurationZoned
intervalIntersectionZoned
intervalLengthZoned
intervalOverlappingDaysZoned
intervalsOverlapZoned
intervalSplitAtZoned
intervalUnionZoned
intervalXorAllZoned
intervalXorZoned
isValidCalendarZonedInterval
isValidZonedInterval
mergeIntervalsZoned
splitIntervalByUnitZoned
map
mapZonedDatesInRange
mapZonedHoursInDay
parse
getZonedOffset
getZonedOffsetAs
parseDateFromZoned
parseDateTimeFromZoned
parseDayFromZoned
parseDayOfWeekFromZoned
parseHourFromZoned
parseMicrosecondFromZoned
parseMillisecondFromZoned
parseMinuteFromZoned
parseMonthFromZoned
parseNanosecondFromZoned
parseRfc2822
parseRfc3339
parseSecondFromZoned
parseTimeFromZoned
parseTimeZoneFromZoned
parseUnitFromZoned
parseWeekFromZoned
parseYearFromZoned
validate
hasDaylightSaving
isValidCalendarZonedDateTime
isValidRfc2822DateTime
Unreleased
isValidRfc3339DateTime
Unreleased
isValidTimeZone
isValidZonedDateTime
isValidZonedRange
By industry
intermodal
Overview
calculate
billingTimeline
chargeableDays
demurrageClock
freeTimeExpiry
multimodalETA
Unreleased
format
Unreleased
bolTimestamp
Unreleased
formatEdifactDate
Unreleased
formatEdifactDatePeriod
Unreleased
formatEdifactDateTime
Unreleased
formatEdifactDateTimePeriod
Unreleased
formatEdifactOffsetDateTime
Unreleased
formatEdifactTime
Unreleased
formatEpcisEvent
Unreleased
formatX12Date
Unreleased
formatX12DateRange
Unreleased
formatX12DateTime
Unreleased
formatX12DateTimeRange
Unreleased
formatX12Time
Unreleased
formatX12TimeElement
Unreleased
parse
Unreleased
classifyEdifactDtmFormat
Unreleased
classifyX12DateTimePeriodFormat
Unreleased
classifyX12TimeCode
Unreleased
parseEdifactDate
Unreleased
parseEdifactDatePeriod
Unreleased
parseEdifactDateTime
Unreleased
parseEdifactDateTimePeriod
Unreleased
parseEdifactOffsetDateTime
Unreleased
parseEdifactTime
Unreleased
parseEpcisEvent
Unreleased
parseX12Date
Unreleased
parseX12DateAndTime
Unreleased
parseX12DateRange
Unreleased
parseX12DateTime
Unreleased
parseX12DateTimeRange
Unreleased
parseX12Time
Unreleased
x12TimeCodeOffset
Unreleased
x12TimeCodeZone
Unreleased
validate
Unreleased
isValidEdifactDate
Unreleased
isValidEdifactDatePeriod
Unreleased
isValidEdifactDateTime
Unreleased
isValidEdifactDateTimePeriod
Unreleased
isValidEdifactDtmFormat
Unreleased
isValidEdifactOffsetDateTime
Unreleased
isValidEdifactTime
Unreleased
isValidEpcisEvent
Unreleased
isValidEpcisEventTime
Unreleased
isValidEpcisTimeZoneOffset
Unreleased
isValidX12Date
Unreleased
isValidX12DateAndTime
Unreleased
isValidX12DateRange
Unreleased
isValidX12DateTime
Unreleased
isValidX12DateTimePeriodFormat
Unreleased
isValidX12DateTimeRange
Unreleased
isValidX12Time
Unreleased
isValidX12TimeCode
Unreleased
transport
Overview
calculate
bestAvailable
crossingTime
cutoffAt
cutoffSchedule
dwellTime
estimateDrift
nextDeparture
punctualityRate
scheduleDelivery
transitTime
compare
classifyPunctuality
isPastCutoff
scheduleDeviation
timeToCutoff
etaAtZone
Guides
Guides
concepts
Concepts
DST Disambiguation
Plain vs Zoned
Correct at the Edges
The Standards
conversion
Conversion
Converting Between Types
Foreign Epoch Bridges
core-date-operations
Core Date Operations
Getting Current Date / Time
Plain Arithmetic
Comparisons
Durations
Parsing
Formatting
Relative Time
Validation
Calendar Systems
Business Calendars and Roll Conventions
Operating Hours and Open-Time SLAs
Nanosecond Precision
Spans
industries
Industries
Transport: Legs and Dwell
Intermodal: Free Time and Demurrage
Intermodal: Billing Deadlines
Transport: Multi-leg Scheduling
Transport: Punctuality and Timestamps
Intermodal: B/L Dates and Multimodal ETA
Intermodal: EDI Timestamps
integration
Integration
Application Integration
Lint Package Selection
AI Agent Skills
intervals
Interval Basics
Containment and Overlap
Set Operations
Splitting and Counting
zoned-date-operations
Zoned Operations
Calendar Boundaries and Zone-Aware Buckets
Offset-Preserving Instants and Local Resolution
Tools
All tools
Billing Deadlines
Connection Checker
Converter Bench
Crossing Clock
Cut-off Countdown
Cut-off Ruler
Cut-off Stack
Delivery Scheduler
Departure Board
DST Inspector
DTM Decoder
Dwell Ledger
ETA Drift Chart
Free Time Ledger
Interval Visualizer
Punctuality Board
Timetable Reader
X12 Time Reader
Zone Planner
Zoned Earth
Scenarios
Scenarios
A 203 Read as UTC
Two Arrivals, One Wall Time: The Fall-Back Night
A B/L Dated a Day Late
A Connection Missed at the Spring-Forward Handoff
Container Dwell: Two Hours, Two Days
A Delay Across the Fall-Back
Demurrage Across a Weekend
Detention Is Not Demurrage
A Dispute Window from a Contract
An Estimate Shown as the Actual
ET Is Not an Offset
An ETA That Forgot the Sailing
A Filing Deadline Anchored to the Wrong Event
Free Time: Which Day Is Day One
Invoice a Day Late
Monthly Billing Without Drift
A Re-Bill Anchored on the Wrong Date
Recurring Meeting Across DST
Storing a Birthday
The EPCIS Offset Nobody Kept
A 26-Hour Rail Leg Across Spring-Forward
Two Days Before Is Not 48 Hours
Mistakes
Common Mistakes
Date Arithmetic
Date Comparison
Type Conversion
Duration
Formatting Date and Time
Formatting Relative Time
Getting the Current Time
Intermodal
Interval Operations
Parsing Date and Time
Transport
Date Validation
Zoned Date Operations
GitHub
Discord
duration/normalize
normalizeDuration
: Roll an ISO 8601 duration string’s small units into larger ones.