Timezone Toolkit

Offsets and DST

TZ_DIFF

Calculates the hour difference between two zones at an instant.

Syntax

=TZ_DIFF(fromZone, toZone, [datetime])

Parameters

NamefromZone
Typetext
DescriptionFirst IANA time zone.
NametoZone
Typetext
DescriptionSecond IANA time zone.
Namedatetime?
Typetext, number, or date
DescriptionInstant interpreted in fromZone. Defaults to the current instant.

Returns

toZone offset minus fromZone offset, in hours.

Example

=TZ_DIFF("America/Los_Angeles", "Europe/London", "2026-06-01")

Result: 8

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