Why do dates sometimes differ between countries?

When the reference instant crosses midnight in another zone, we show the correct local calendar date there. That is expected—not an error.

Which country should be the reference?

Pick whichever side owns the meeting invite. The math is symmetric: the tool converts one absolute instant to every selected zone.

Does live mode follow my device clock?

Live mode anchors on the current UTC instant and projects it using each country's zone rules. Your device clock supplies the starting instant.

COMPARATEUR

Comparateur d’heure mondiale

Sélectionnez jusqu’à quatre pays, définissez une date et une heure de référence, et voyez l’instant exact dans chaque lieu.

Quand il est 14:39 en Corée du Sud, il est 14:39 en Japon.

Pays de référence

Date

Heure

Heure en direct

Les heures ci‑dessous se mettent à jour lorsque vous modifiez la date et l’heure de référence.

Corée du Sud

Asia/Seoul

Référence

14:39

mar., 1 sept.

—

Japon

Asia/Tokyo

14:39

mar., 1 sept.

Écart vs. référence+0m

About the time zone comparator

The comparator answers a precise question: if it is a given date and time in one country, what is the exact same instant elsewhere? Unlike adding fixed hour offsets in your head, we apply IANA rules so daylight saving and regional exceptions stay correct.

How to compare time zones

Add at least two countries using the search control.
Choose a reference country and set its local date and time (or enable live mode).
Review equivalent local times in every row, including date rollovers.
Adjust the reference or swap countries until you find a workable meeting window.

Example: Madrid and Tokyo

Suppose you want a call when it is 10:00 in Madrid. Add Spain and Japan, set Spain as reference with 10:00 on your chosen date, and read the matching time in Tokyo—often late afternoon or evening. Always confirm on the actual meeting date because DST may differ.

Comparator FAQ

Why do dates sometimes differ between countries?: When the reference instant crosses midnight in another zone, we show the correct local calendar date there. That is expected—not an error.
Which country should be the reference?: Pick whichever side owns the meeting invite. The math is symmetric: the tool converts one absolute instant to every selected zone.
Does live mode follow my device clock?: Live mode anchors on the current UTC instant and projects it using each country's zone rules. Your device clock supplies the starting instant.