Clock roster
{{ worldClockRows.length }} clocks
{{ timezoneLabel }} basis · UTC {{ utcOffsetLabel }}
{{ timezoneLabel }} UTC {{ utcOffsetLabel }} {{ handoffBadge }} {{ hourCycleLabel }}
Use Local for the device wall clock, or UTC for cross-region handoff notes.
Enter one zone per line, such as local, UTC, Asia/Kuala_Lumpur, Europe/London, or America/New_York.
Valid zones: {{ validZoneCount }} · {{ zoneWarnings.join(' · ') }}
Use 24-hour style for operational notes, or Auto when local locale conventions matter.
Use a roster starter, then edit the zone list above if your handoff needs a different site.
World clock roster
Pick the local source time to convert across every world clock zone.
Set the planned length of the handoff or meeting.
minutes
Use 24-hour local times for each zone; weekdays are Monday through Friday.
to
{{ showSeconds ? 'Display format includes seconds.' : 'Display format stays at minute precision.' }}
{{ showSeconds ? 'Shown' : 'Hidden' }}
Sync favors overlap, display favors readability, audit favors immutable timestamp evidence.
Give exported calendar text a concise handoff title.
Leave blank for remote handoffs, or add a room, bridge, or channel name.
Metric Value Copy
{{ row.label }} {{ row.value }}
Zone Current time Date UTC offset Delta vs basis Work state Copy
{{ row.label }} {{ row.time }} {{ row.date }} {{ row.offsetLabel }} {{ row.deltaLabel }} {{ row.workState }}
Zone Handoff local time Date shift Offset at handoff Work state Handoff note Copy
{{ row.label }} {{ row.localDateTime }} {{ row.dateShiftLabel }} {{ row.offsetLabel }} {{ row.workState }} {{ row.note }} 

        


        

          

            

              

                
                
              

            

          

          

        

      


    

  

                

                

                    

                        

                            Tags: Date Time, Diagnostics
                        

                        

                            
                            
                        

                    

                

            

        

    


                    
        

        

        

            

            
        

        


                    

                

                

                    

                                                                                

                                
                                    
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      The Online Clock turns the current instant into a practical working-time view. It shows local time, UTC, Unix seconds, selected world zones, and a handoff matrix so you can check whether a meeting, shift change, or operational update lands inside normal working hours for each place.
    

    

      Use it when the problem is not just "what time is it?" but "what time is it for everyone involved?" The clock can compare zones, flag weekend and outside-window cases, switch between 12-hour and 24-hour display, and prepare plain calendar invite text for the selected handoff time.
    

    

      The tool is best for quick coordination checks, release-room dashboards, support rotations, travel planning, and documentation where UTC offsets and local dates need to be shown side by side.
    


    

      A diagram showing one current instant branching into local time, UTC, UTC offset, and handoff rows.
      

        One instant can have several useful readings: a local label, a UTC basis, an offset, and a coordination status for each selected zone.
      

    

  






  

    
How to Use This Tool

    
    
      
  1. Choose whether the primary clock should be based on Local time or UTC.
    2. 
      
  2. Add IANA time zone names such as America/New_York, Europe/London, Asia/Tokyo, UTC, or local. Presets can fill common operational sets.
    3. 
      
  3. Select 12-hour, 24-hour, or automatic clock formatting.
    4. 
      
  4. Set a handoff time and duration when you need to compare a meeting or shift window across zones.
    5. 
      
  5. Define the normal work window used for the handoff badges. A same start and end time means a 24-hour coverage window.
    6. 
      
  6. Open the result tabs for clock details, the world clock board, the handoff matrix, offset bars, calendar invite text, or JSON export.
    7. 
    

    

      If a zone is rejected, check the spelling against the standard area/location form. The tool caps very large zone lists so the board and charts stay readable.
    

  






  

    
Interpreting Results

    

      Clock Details gives the selected basis time, device zone, UTC offset, Unix seconds, date parts, and handoff summary. World Clock Board is the fastest way to see whether a location is on the same calendar date, a different date, or a different business day.
    

    

      Handoff Matrix focuses on the selected handoff window. It labels each zone as inside work time, outside work time, weekend, or date-shifted. The overall badge is intentionally conservative: if only some locations overlap the work window, treat it as a coordination warning rather than a failure.
    

    

      The offset chart is a comparison aid, not a legal time source. For payroll, aviation, court deadlines, or regulated filings, confirm the official time zone rule and the target calendar system separately.
    

  






  

    
Technical Details

    

      The clock treats UTC as the shared reference instant, then formats that instant for each selected time zone. Daylight-saving changes are handled by the time zone rules available to the browser, so offsets can change by date even when the zone name stays the same.
    


    
Formula Core

    

      Unix seconds are the whole seconds elapsed since the Unix epoch, using UTC rather than a local civil clock.
    

    
      
        Unix seconds
        =
        ⌊
        
          
            current UTC milliseconds
            -
            epoch UTC milliseconds
          
          1000
        
        ⌋
      
    
    

      Zone offsets are displayed as signed hours and minutes from UTC for the selected instant.
    

    
      
        offset minutes
        =
        
          
            zone civil time expressed as UTC milliseconds
            -
            UTC milliseconds
          
          60000
        
      
    

    

      

        
          

            Rule
            How it is applied
          

        
        
          

            Normal work window
            A time is inside the window when it is on or after the start and before the end.
          

          

            Overnight window
            When the end time is earlier than the start time, the inside period wraps through midnight.
          

          

            All-day window
            When start and end are equal, the window is treated as open for the whole day.
          

          

            Weekend flag
            Saturday and Sunday are flagged separately from ordinary outside-window times.
          

        
      

    

  






  

    
Limitations and Privacy

    
    
      
  • The displayed instant follows your device clock. If the device clock is wrong, the clock output will be wrong.
    • 
      
  • Time zone labels depend on current browser support for IANA zone names and daylight-saving transitions.
    • 
      
  • Calendar invite text should be checked in the calendar app that imports it, especially around daylight-saving changes.
    • 
      
  • The calculation runs in the browser tab. The tool does not need your calendar account to produce the invite text.
    • 
    

  






  

    
Worked Examples

    

      Global standup. Add America/New_York, Europe/London, and Asia/Singapore, set the handoff time, and compare the Handoff Matrix before sending the invite.
    

    

      UTC audit note. Switch the primary basis to UTC, enable seconds, and copy the Unix seconds plus UTC offset into an incident or release note.
    

    

      Follow-the-sun rotation. Use a zone preset, set the work window to the team norm, then look for the zones marked inside work time during the proposed transfer window.
    

  






  

    
FAQ

    
Why does an offset change for the same city?

    

      Many zones observe daylight-saving or other civil-time changes. The offset belongs to a specific instant, not permanently to the city.
    

    
Why is my typed zone rejected?

    

      Use a standard IANA zone name such as America/Los_Angeles. Abbreviations such as PST or CST are ambiguous and are not reliable for world clocks.
    

    
Can I use the calendar invite text directly?

    

      Yes for simple handoff holds, but preview it after import. Calendar apps may add their own reminders, conferencing, or timezone display choices.
    

  






  

    
References