Date functions

A Date contains a calendar day without a time of day. Date literals use #yyyy-MM-dd#, for example #2026-08-31#.

`AdjustMonth`

Moves a date by a whole number of calendar months.

Syntax: AdjustMonth(date, months)
Requires: a Date and a whole Numeric month count. Negative counts move backward.
Returns: Date.
Best for: monthly renewals, due dates, and reporting cycles.

AdjustMonth([Start Date], 3)

When the target month is shorter, the day is clamped to that month’s last valid day.

`AdjustYear`

Moves a date by a whole number of calendar years.

Syntax: AdjustYear(date, years)
Requires: a Date and a whole Numeric year count. Negative counts move backward.
Returns: Date.
Best for: anniversaries, annual renewals, and age windows.

AdjustYear([Certification Date], 1)

Moving February 29 into a non-leap year uses the last valid day of February.

`Date`

Creates a calendar date from numeric components.

Syntax: Date(year, month, day)
Requires: three whole Numeric values that form a valid date.
Returns: Date.
Best for: fixed dates and dates assembled from separate imported fields.

Date(2026, 8, 31)

`Day`

Returns the day of the month.

Syntax: Day(date)
Requires: a Date.
Returns: Numeric from 1 through 31.
Best for: monthly grouping and calendar labels.

Day([Inspection Date])

`DayOfWeek`

Returns the weekday number, starting with Sunday.

Syntax: DayOfWeek(date)
Requires: a Date.
Returns: Numeric: Sunday is 0, Monday 1, through Saturday 6.
Best for: weekday rules and weekend checks.

In(DayOfWeek([Inspection Date]), 0, 6)

`DayOfYear`

Returns how many days a date follows January 1.

Syntax: DayOfYear(date)
Requires: a Date.
Returns: zero-based Numeric: January 1 is 0.
Best for: seasonal grouping and day-of-year comparisons.

DayOfYear([Harvest Date])

`FirstDayOfMonth`

Returns the first date in the same month.

Syntax: FirstDayOfMonth(date)
Requires: a Date.
Returns: Date.
Best for: monthly report windows and grouping.

FirstDayOfMonth([Invoice Date])

`FirstDayOfPeriod`

Finds the first day of a repeating fixed-length period anchored to a reference date.

Syntax: FirstDayOfPeriod(date, duration, referenceDate)
Requires: two Dates and a positive Duration. Fractional days are discarded toward zero, so the Duration must contain at least one full day.
Returns: Date.
Best for: custom 7-day, 14-day, or other fixed reporting cycles.

FirstDayOfPeriod([Inspection Date], Days(14), #2026-01-05#)

`FirstDayOfQuarter`

Returns the first date in the same calendar quarter.

Syntax: FirstDayOfQuarter(date)
Requires: a Date.
Returns: Date.
Best for: quarterly reports and targets.

FirstDayOfQuarter([Invoice Date])

`FirstDayOfWeek`

Returns the Sunday at the start of the date’s week.

Syntax: FirstDayOfWeek(date)
Requires: a Date.
Returns: Date.
Best for: Sunday-to-Saturday reporting windows.

FirstDayOfWeek([Inspection Date])

`FirstDayOfYear`

Returns January 1 in the same year.

Syntax: FirstDayOfYear(date)
Requires: a Date.
Returns: Date.
Best for: year-to-date reporting.

FirstDayOfYear([Invoice Date])

`ISOWeek`

Returns the ISO 8601 week number.

Syntax: ISOWeek(date)
Requires: a Date.
Returns: Numeric week number using Monday as the first weekday and the ISO first-week rule.
Best for: internationally consistent weekly reporting.

ISOWeek([Inspection Date])

`IsLeapDay`

Checks whether a date is February 29.

Syntax: IsLeapDay(date)
Requires: a Date.
Returns: Boolean.
Best for: anniversary and renewal edge cases.

IsLeapDay([Start Date])

`IsLeapYear`

Checks whether a date’s year, or a supplied year number, is a leap year.

Syntax: IsLeapYear(dateOrYear)
Requires: a Date or whole Numeric year.
Returns: Boolean.
Best for: February and annual-calendar rules.

IsLeapYear([Inspection Date])
IsLeapYear(2028)

`LastDayOfMonth`

Returns the last date in the same month.

Syntax: LastDayOfMonth(date)
Requires: a Date.
Returns: Date.
Best for: monthly deadlines and report ranges.

LastDayOfMonth([Invoice Date])

`LastDayOfPeriod`

Finds the last day of a repeating fixed-length period anchored to a reference date.

Syntax: LastDayOfPeriod(date, duration, referenceDate)
Requires: two Dates and a positive Duration. Fractional days are discarded toward zero, so the Duration must contain at least one full day.
Returns: Date.
Best for: the closing date of custom reporting cycles.

LastDayOfPeriod([Inspection Date], Days(14), #2026-01-05#)

`LastDayOfQuarter`

Returns the last date in the same calendar quarter.

Syntax: LastDayOfQuarter(date)
Requires: a Date.
Returns: Date.
Best for: quarterly deadlines and report ranges.

LastDayOfQuarter([Invoice Date])

`LastDayOfWeek`

Returns the Saturday at the end of the date’s week.

Syntax: LastDayOfWeek(date)
Requires: a Date.
Returns: Date.
Best for: Sunday-to-Saturday reporting windows.

LastDayOfWeek([Inspection Date])

`LastDayOfYear`

Returns December 31 in the same year.

Syntax: LastDayOfYear(date)
Requires: a Date.
Returns: Date.
Best for: annual report and validity windows.

LastDayOfYear([Invoice Date])

`Month`

Returns the calendar month number.

Syntax: Month(date)
Requires: a Date.
Returns: Numeric from 1 for January through 12 for December.
Best for: monthly grouping and conditional rules.

Month([Harvest Date])

`MonthsBetween`

Counts month boundaries crossed from one date to another.

Syntax: MonthsBetween(startDate, endDate)
Requires: two Dates.
Returns: signed Numeric boundary count.
Best for: calendar-month reporting buckets rather than exact elapsed time.

MonthsBetween([Start Date], [End Date])

Day numbers do not affect the result; January 31 to February 1 crosses one month boundary.

`NextDayOfWeek`

Returns the next requested weekday strictly after a date.

Syntax: NextDayOfWeek(date, weekday)
Requires: a Date and a whole Numeric weekday from 0 (Sunday) through 6 (Saturday).
Returns: Date.
Best for: next collection, meeting, or processing day rules.

NextDayOfWeek([Order Date], 1)

If the supplied date is already that weekday, the result is seven days later.

`PrevDayOfWeek`

Returns the requested weekday strictly before a date.

Syntax: PrevDayOfWeek(date, weekday)
Requires: a Date and a whole Numeric weekday from 0 (Sunday) through 6 (Saturday).
Returns: Date.
Best for: previous cut-off or reporting-day rules.

PrevDayOfWeek([Order Date], 5)

If the supplied date is already that weekday, the result is seven days earlier.

`Quarter`

Returns the calendar quarter number.

Syntax: Quarter(date)
Requires: a Date.
Returns: Numeric from 1 through 4.
Best for: quarterly grouping and targets.

Quarter([Invoice Date])

`QuartersBetween`

Counts quarter boundaries crossed from one date to another.

Syntax: QuartersBetween(startDate, endDate)
Requires: two Dates.
Returns: signed Numeric boundary count.
Best for: calendar-quarter reporting buckets.

QuartersBetween([Start Date], [End Date])

`Today`

Returns the current date in the active formula timezone.

Syntax: Today()
Requires: the evaluation clock and timezone supplied by Dsync.
Returns: Date.
Best for: due, overdue, age, and validity checks.

[Due Date] < Today()

Every Today() call in one evaluation observes the same date.

`Week`

Returns the week number using a locale-based or explicitly selected first weekday.

Syntax: Week(date[, firstWeekday])
Requires: a Date and optional whole Numeric weekday from 0 (Sunday) through 6 (Saturday). Without it, the active locale chooses the first weekday.
Returns: Numeric week number.
Best for: locally configured weekly reports.

Week([Inspection Date])
Week([Inspection Date], 1)

Use ISOWeek when reports must follow ISO 8601 everywhere.

`Workday`

Moves a date by a number of working days.

Syntax: Workday(date, amount[, weekend])
Requires: a Date; a whole Numeric amount or a Duration; and optional weekend Text. Fractional days in a Duration are discarded toward zero. Negative amounts move backward.
Returns: Date.
Best for: business deadlines and service schedules.

Workday([Submitted Date], 5)
Workday([Submitted Date], 5, "67")

The default weekend is Saturday and Sunday. Custom weekend text can contain one or two weekday digits (1 Monday through 7 Sunday), or a seven-character Monday-to-Sunday mask where 1 marks a weekend day.

`Workdays`

Counts working days between two dates, including both endpoints.

Syntax: Workdays(startDate, endDate[, weekend])
Requires: two Dates and optional weekend Text in the same format as Workday.
Returns: Duration containing the signed number of working days.
Best for: turnaround time and service-level reporting.

ToDays(Workdays([Opened Date], [Closed Date]))

The result is negative when the end date is before the start date.

`Year`

Returns the calendar year.

Syntax: Year(date)
Requires: a Date.
Returns: Numeric year.
Best for: annual grouping and labels.

Year([Harvest Date])

`YearsBetween`

Counts year boundaries crossed from one date to another.

Syntax: YearsBetween(startDate, endDate)
Requires: two Dates.
Returns: signed Numeric boundary count.
Best for: calendar-year buckets rather than exact anniversaries.

YearsBetween([Start Date], [End Date])

Month and day do not affect this boundary count.

Use AdjustMonth and AdjustYear for calendar movement. Use Days and Duration arithmetic when you mean a fixed elapsed amount.

Dsync guides

Function setup

Configuration

Formula language

Formula reference

`AdjustMonth`

`AdjustYear`

`Date`

`Day`

`DayOfWeek`

`DayOfYear`

`FirstDayOfMonth`

`FirstDayOfPeriod`

`FirstDayOfQuarter`

`FirstDayOfWeek`

`FirstDayOfYear`

`ISOWeek`

`IsLeapDay`

`IsLeapYear`

`LastDayOfMonth`

`LastDayOfPeriod`

`LastDayOfQuarter`

`LastDayOfWeek`

`LastDayOfYear`

`Month`

`MonthsBetween`

`NextDayOfWeek`

`PrevDayOfWeek`

`Quarter`

`QuartersBetween`

`Today`

`Week`

`Workday`

`Workdays`

`Year`

`YearsBetween`

​AdjustMonth

​AdjustYear

​Date

​Day

​DayOfWeek

​DayOfYear

​FirstDayOfMonth

​FirstDayOfPeriod

​FirstDayOfQuarter

​FirstDayOfWeek

​FirstDayOfYear

​ISOWeek

​IsLeapDay

​IsLeapYear

​LastDayOfMonth

​LastDayOfPeriod

​LastDayOfQuarter

​LastDayOfWeek

​LastDayOfYear

​Month

​MonthsBetween

​NextDayOfWeek

​PrevDayOfWeek

​Quarter

​QuartersBetween

​Today

​Week

​Workday

​Workdays

​Year

​YearsBetween

`AdjustMonth`

`AdjustYear`

`Date`

`Day`

`DayOfWeek`

`DayOfYear`

`FirstDayOfMonth`

`FirstDayOfPeriod`

`FirstDayOfQuarter`

`FirstDayOfWeek`

`FirstDayOfYear`

`ISOWeek`

`IsLeapDay`

`IsLeapYear`

`LastDayOfMonth`

`LastDayOfPeriod`

`LastDayOfQuarter`

`LastDayOfWeek`

`LastDayOfYear`

`Month`

`MonthsBetween`

`NextDayOfWeek`

`PrevDayOfWeek`

`Quarter`

`QuartersBetween`

`Today`

`Week`

`Workday`

`Workdays`

`Year`

`YearsBetween`