About

In the era of hyper-distributed teams, the greatest friction isn't bandwidth - it's temporal dissonance. Scheduling a critical synchronization between London, Tokyo, and San Francisco often involves mental gymnastics that lead to missed connections and sleep deprivation. Accuracy in time zone conversion is not merely a convenience; it is an operational necessity.

This tool eliminates the cognitive load of manual time calculation. By leveraging the IANA Time Zone Database directly, it accounts for Daylight Saving Time (DST) rules automatically, which vary wildly by jurisdiction. The integrated Meeting Planner allows you to project the temporal state of the entire globe into the future, instantly identifying the Golden Window - that rare overlap where all stakeholders are awake and within business hours.

Formulas

The calculation of local time T_local relies on the Coordinated Universal Time T_UTC and the specific zone offset Δ_zone, which is a function of both location and date (due to DST).

{

T_local = T_UTC + Offset(Zone, Date)where Offset ∈ Z × 15min

To determine the business overlap efficiency η for a set of N cities, we evaluate the intersection of working hours:

N∩i=1

(9:00 ≤ h_i ≤ 17:00)

Reference Data

Region / City	IANA Zone Code	Std. Offset (UTC)	DST Observed
London, UK	Europe/London	+0 / +1	Yes
New York, USA	America/New_York	-5 / -4	Yes
Tokyo, Japan	Asia/Tokyo	+9	No
Sydney, Australia	Australia/Sydney	+10 / +11	Yes
Dubai, UAE	Asia/Dubai	+4	No
Berlin, Germany	Europe/Berlin	+1 / +2	Yes
Moscow, Russia	Europe/Moscow	+3	No
Los Angeles, USA	America/Los_Angeles	-8 / -7	Yes
Singapore	Asia/Singapore	+8	No
Mumbai, India	Asia/Kolkata	+5:30	No
Sao Paulo, Brazil	America/Sao_Paulo	-3	No
Johannesburg, SA	Africa/Johannesburg	+2	No

Frequently Asked Questions

We utilize the browser's native Intl.DateTimeFormat API which queries the IANA Time Zone Database. This ensures that DST transitions are applied automatically and accurately for every specific region, even those with non-standard change dates.

The visual indicators (green glow/opacity) are triggered when the local time in a specific city falls between 09:00 and 17:00 (5 PM). This is a fixed standard working window used to quickly identify overlap availability.

This is a relative date indicator. It compares the calendar date of the remote city to your local system time. If Tokyo is 14 hours ahead, it may already be "Tomorrow" relative to your location in New York.

No. The Meeting Planner slider applies a static offset to the current time. If you drag the slider to +2 hours, the clocks will continue to tick second-by-second, but they will remain 2 hours ahead of the actual current time until you reset.