About Time Zone Calculator

Dual-mode time zone tool: conversion mode translates a specific date/time between any two of 20 major time zones, while world clock mode displays live-updating clocks for eight cities (New York, London, Paris, Tokyo, Sydney, Dubai, Los Angeles, Singapore). Conversion results show the hour offset and can be saved to a scrollable history, which exports as CSV.

• 20 time zones including São Paulo, Cairo, Singapore, Mexico City, and Honolulu
• Auto-detects the user’s local time zone via Intl.DateTimeFormat().resolvedOptions()
• Conversion history stores up to 10 entries with source/target times, zones, and hour difference
• World clock mode shows eight simultaneous city clocks with UTC offset labels, refreshing every second
• History exportable as CSV with ISO 8601 timestamps

Frequently Asked Questions

How is this different from the Time Converter tool?

The Time Zone Calculator adds a world clock mode with eight simultaneous city displays, conversion history with CSV export, and five additional time zones. The Time Converter is simpler—a single conversion panel with a sidebar clock.

Why do some time zones have 30 or 45-minute offsets?

Not all countries adopted hourly offsets from UTC. India uses UTC+5:30, Nepal uses UTC+5:45, and several other regions use half-hour or 45-minute offsets for historical and political reasons. The calculator handles all of these correctly.