Time zones are not always a whole number of hours apart

Minutes matter when comparing places such as India and Nepal.

WhatTimeIsIt Published 11 October 2026

Do not round away the minutes

A UTC offset can include minutes. Two locations do not have to differ by a whole number of hours, and a converter should preserve that detail. For example, Mumbai uses Asia/Kolkata and Kathmandu uses Asia/Kathmandu. Their modern standard offsets are UTC+05:30 and UTC+05:45 respectively. That makes Kathmandu fifteen minutes ahead in this example, even though both locations may be loosely described as about five hours ahead of UTC.

Work with the full offset

To convert a specific time, account for both hours and minutes. At 12:00 UTC, UTC+05:30 gives 17:30, while UTC+05:45 gives 17:45. A meeting announced as 17:30 in Mumbai is therefore not 17:30 in Kathmandu. Use the Mumbai–Kathmandu comparison or the converter instead of rounding a remembered difference. Preserve the date if the calculation crosses midnight.

A fixed offset does not describe every place forever

The examples describe contemporary rules, not a promise that policies never change. Geographic identifiers hold date-dependent rules and historical information; a number such as +05:30 is only an offset. Other locations can have seasonal changes or different historical offsets. When planning a future appointment, choose the actual city and date rather than selecting a nearby region whose current clock happens to be similar.

Design schedules that respect minute offsets

International teams should consider starts at quarter-hour or half-hour marks when that makes local schedules easier to use. Do not force every event to an hour boundary in the organizer’s zone without checking the result elsewhere. In software and spreadsheets, store offsets with their minutes rather than as rounded integers. Our UTC explanation covers the underlying arithmetic, and the meeting guide turns a correct conversion into a practical shared schedule.