Neatbo.

Time zones and UTC formatting

Resolve time zones and daylight-saving ambiguity, or format an instant in UTC.

Browser-local processingInputDate + zonesOutputDate
  1. 1Add input
  2. 2Adjust settings
  3. 3Get your result

Tool input and files are processed in this browser without being uploaded.

Your input

Inputs are kept temporarily in this tab when switching tools. Refreshing or closing clears them; large results may need to be regenerated.

⌘ / Ctrl + Enter to run

Use a zone name such as Asia/Shanghai or America/New_York. A fixed UTC offset cannot describe daylight-saving rules.

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Preparing the tool…

Before you start

Resolve time zones and daylight-saving ambiguity, or format an instant in UTC. Convert a local wall-clock time between IANA timezones using browser timezone data. Nonexistent DST times are rejected; repeated times require an explicit earlier or later choice.

How to use this tool

  1. Choose time-zone conversion or UTC formatting above the input.
  2. Enter a date-time; conversion needs source and target IANA zones and a choice for repeated local times.
  3. Review the Date result, then use the available copy or download controls.

Supported inputs and limits

Pasted text is limited to 1 MiB; review the result before using it.

Tokens: YYYY MM DD HH mm ss. Output uses UTC, including when the input has a different offset.

Output uses UTC; any input offset is applied before conversion.

Files and input are processed in this browser. No account needed.

Worked example

Example input

2024-01-01T00:00:00
Example options
{
  "fromZone": "UTC",
  "toZone": "Asia/Kathmandu"
}

Example output

{
  "from": "2024-01-01T00:00:00",
  "fromZone": "UTC",
  "to": "2024-01-01T05:45:00",
  "toZone": "Asia/Kathmandu",
  "iso": "2024-01-01T00:00:00.000Z",
  "milliseconds": 1704067200000
}

When something does not work

Check the input unit, calendar date and IANA time zone. A skipped daylight-saving time has no matching instant; a repeated time requires an explicit earlier/later choice.

Frequently asked questions

Where are the combined operations?

Use Task to choose Time zone conversion, UTC formatting. Some parameters apply only to their corresponding task; run again and inspect the result after changing modes.

Are my files uploaded?

No. Files and tool input are processed in your browser. Moving around the site can keep a temporary workspace in the same tab. Refreshing or closing the tab clears it, so download results you want to keep.

What should I check in this result?

Convert a local wall-clock time between IANA timezones using browser timezone data. Nonexistent DST times are rejected; repeated times require an explicit earlier or later choice.

Documentation & further reading

Date and time guide: timestamps, zones, workdays and durations →Time zones, workdays and rounding: explain calculation results →

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