Timezone Toolkit reference

Timezone Toolkit

Convert, compare, and schedule across time zones with 29 DST-aware TZ_ functions that behave like native spreadsheet formulas.

29 custom functions

DST-aware IANA zones

Range input support

No external API calls

Global operations sheets

Convert timestamps from vendors, CRMs, logs, and handoff docs without leaving the formula bar.

Meeting planning

Show one meeting across every office and find real workday overlap before inviting the team.

Timezone cleanup

Normalize offsets, abbreviations, ISO strings, Unix timestamps, and date parts into dependable columns.

Convert

5 functions

TZ_CONVERT

Converts a date or time from one time zone to another.

TZ_TO_UTC

Converts a zoned date/time into UTC.

TZ_FROM_UTC

Converts a UTC date/time into a target time zone.

TZ_NOW

Returns the current date and time in a time zone.

TZ_TODAY

Returns today's date in a selected time zone.

Offsets and DST

8 functions

TZ_OFFSET

Returns a DST-aware UTC offset string for a time zone.

TZ_OFFSET_HOURS

Returns a DST-aware UTC offset as decimal hours.

TZ_DIFF

Calculates the hour difference between two zones at an instant.

TZ_IS_DST

Checks whether daylight saving time is active in a zone.

TZ_ABBR

Returns the short time zone abbreviation for an instant.

TZ_NAME

Returns the long localized time zone name for an instant.

TZ_DST_NEXT

Finds the next offset or DST transition for a zone.

TZ_DST_PREVIOUS

Finds the previous offset or DST transition for a zone.

Parse, Format, and Epochs

5 functions

TZ_FORMAT

Formats a date/time in a zone using presets or Luxon tokens.

TZ_PARSE

Parses date/time text into a normalized ISO string with offset.

TZ_TO_ISO

Renders a date/time as an ISO 8601 string with offset.

TZ_TO_UNIX

Converts a zoned date/time to a Unix timestamp.

TZ_FROM_UNIX

Converts a Unix timestamp into a zoned date/time.

Components and Math

4 functions

TZ_PART

Extracts a single date/time component as seen in a zone.

TZ_ADD

Adds or subtracts a duration in a zone.

TZ_BETWEEN

Measures elapsed time between two zoned date/times.

TZ_RELATIVE

Creates a human-friendly relative time phrase.

Zones, Lookup, and Scheduling

7 functions

TZ_VALIDATE

Checks whether a zone string is recognized.

TZ_GUESS

Returns the spreadsheet/script time zone.

TZ_LIST

Lists available IANA time zones, optionally filtered.

TZ_LOOKUP

Finds time zones by city, country, or abbreviation.

TZ_COUNTRY

Returns the country associated with an IANA time zone.

TZ_MEETING

Shows one meeting time across many target zones.

TZ_WORKDAY_OVERLAP

Finds overlapping business hours between two zones.