Unix Timestamp Converter

Convert Unix seconds or milliseconds to an ISO date and local time.

How it works

Unix time is measured from 1970-01-01 UTC. Select the unit used by your API or log.

Date = new Date(timestamp × unit multiplier).

Debugging scenario

Copy a synthetic event timestamp from the same API field as the incident, select seconds or milliseconds and compare ISO UTC with the source log. Then view local time only for presentation and record the timezone used in the incident timeline.

How to interpret the result

The ISO result is an instant in UTC; local output depends on the browser timezone and daylight-saving rules. A value off by about 1,000 times usually indicates unit confusion, while an hour-scale difference usually points to timezone presentation rather than the stored instant.

Input reference

Timestamp
Example default: 1752883200
Unit
Example default: Seconds

Common mistakes

  • Pasting secrets, credentials, customer records or other production data into a browser tool or shareable URL.
  • Removing the timezone from a displayed date or mixing seconds and milliseconds in the same pipeline.
  • Treating a convenient preview as validation by the target runtime, parser, database or security control.

Before using the result

  1. Reduce the input to a synthetic example that still reproduces the behavior.
  2. Confirm the documented unit and compare UTC instants at producer, storage and consumer boundaries.
  3. Add the accepted input and expected output to the project regression tests before release.

Questions to check before production use

Which timezone is used?

ISO output is UTC; local output uses your browser timezone.

Why are my values off by 1,000?

Your source may use seconds while the tool is set to milliseconds, or vice versa.

Independent developer utility. Review output before using it in production.

Detailed developer guide

Time, URLs and web interoperability: test boundaries, not appearances

Web values often look readable while carrying hidden unit, context or compatibility assumptions. This guide traces each value through the system that actually consumes it.

Read the guide