Convertisseur de Fuseau Horaire Gratuit en Ligne
Convertissez des heures entre les fuseaux horaires du monde entier.
A time zone converter translates a specific date and time from one time zone into the equivalent local time in another — accounting for each zone's UTC offset and any daylight saving time adjustments automatically.
Common time zone conversions
- New York → London: ET is UTC−5 (EST) / UTC−4 (EDT); London is UTC+0 (GMT) / UTC+1 (BST) — typically 5 hours ahead
- London → Dubai: Dubai is UTC+4 all year (no DST) — typically 4 hours ahead of GMT
- New York → Tokyo: JST is UTC+9 — Tokyo is typically 13–14 hours ahead of New York depending on DST
- London → Singapore: SGT is UTC+8 all year — Singapore is 7–8 hours ahead of London
Daylight saving time
Most of North America and Europe observe daylight saving time (DST), advancing clocks by 1 hour in spring and reverting in autumn. The US switches in March and November; the EU switches in the last Sunday of March and October. Countries near the equator and in Asia (China, Japan, Singapore, India) do not observe DST — their UTC offset stays constant year-round, which can make cross-timezone calculations shift by ±1 hour seasonally.
Understanding UTC offsets
UTC (Coordinated Universal Time) is the global time standard. Every time zone is expressed as an offset from UTC: New York is UTC−5 (EST), Paris is UTC+1 (CET), Kolkata is UTC+5:30 (IST — one of the few half-hour offsets). When scheduling international meetings, convert all times to UTC first for the clearest comparison.
Frequently Asked Questions
What is the best time to schedule a meeting between New York and London?
New York (EST, UTC-5 / EDT UTC-4) and London (GMT UTC+0 / BST UTC+1) have a 5-hour difference in winter and 4 hours in summer. 9 AM New York = 2 PM London. Overlap window: 9 AM–1 PM New York / 2 PM–6 PM London.
What are UTC and GMT and are they the same?
UTC (Coordinated Universal Time) is the world's primary time standard. GMT (Greenwich Mean Time) is a time zone that equals UTC+0 in winter. For practical purposes, UTC and GMT are interchangeable — UTC is the more precise scientific term.
How do I find a meeting time that works across multiple time zones?
The tool shows a clock grid for multiple cities simultaneously. Common windows for global meetings: 9 AM–10 AM UTC covers early morning for US East, late morning for Europe, and late evening for Asia-Pacific.
When does daylight saving time change in 2025?
US (most states): clocks spring forward 2nd Sunday in March and fall back 1st Sunday in November. EU: last Sunday in March and October. Australia: first Sunday in October and April. Many countries don't observe DST at all.
What is the difference between a time zone and a UTC offset?
A UTC offset (e.g. UTC+5:30) is a fixed difference from UTC. A time zone (e.g. "America/New_York") is a geographic region that follows a set of rules including DST transitions. One time zone can have two different UTC offsets (summer vs winter).
Is the Convertisseur de Fuseau Horaire free to use?
Yes, the Convertisseur de Fuseau Horaire on Allio Tools is completely free with no sign-up or registration required. It works directly in your browser.
How does the Convertisseur de Fuseau Horaire work?
Convertissez des heures entre les fuseaux horaires du monde entier. No data is sent to a server — everything runs locally in your browser for maximum privacy and speed.
Do I need to install anything to use the Convertisseur de Fuseau Horaire?
No installation needed. The Convertisseur de Fuseau Horaire runs entirely in your web browser on any device — desktop, tablet, or mobile.
Is my data safe when using the Convertisseur de Fuseau Horaire?
Completely safe. The Convertisseur de Fuseau Horaire processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.
Does the Convertisseur de Fuseau Horaire work offline?
After the page loads for the first time, the Convertisseur de Fuseau Horaire works without an internet connection for all client-side processing. Tools that fetch live external data (such as DNS or network lookups) require an active connection.
Does the Convertisseur de Fuseau Horaire automatically account for daylight saving time?
Yes. The Convertisseur de Fuseau Horaire uses your browser's built-in time zone data, which includes daylight saving time rules for all supported time zones, keeping results accurate year-round.
How does the Convertisseur de Fuseau Horaire handle daylight saving time and leap years?
The Convertisseur de Fuseau Horaire uses your browser's built-in Intl and Date APIs, which automatically account for daylight saving time transitions, leap years, and regional time zone rules. You do not need to make any manual adjustments for these calendar events.
Does the Convertisseur de Fuseau Horaire work on all browsers?
Yes. The Convertisseur de Fuseau Horaire is built with standard browser APIs and works on all modern browsers including Chrome, Firefox, Safari, and Edge — on both desktop and mobile. No plugins, extensions, or third-party software are required.
How do I save or export my results from the Convertisseur de Fuseau Horaire?
Select and copy the result text to paste into any document or app. For image tools, a Download button saves the file directly to your device. Your browser's built-in screenshot function also captures results quickly. No account or login is required.