Date & Time Tools
Timestamp Converter
Convert Unix timestamps to readable dates and convert local date-time values back to epoch time.
Timestamp to ISO: 2026-05-27T15:50:22.000Z
Date to seconds: 1779897000
Date to milliseconds: 1779897000000About this Timestamp Converter
Timestamp Converter turns Unix epoch values into readable dates and converts readable dates back to epoch. It supports seconds, milliseconds, and microseconds; multiple timezones; and ISO 8601 format. Engineers use it daily to debug logs, audit trails, JWT expiration claims, scheduled jobs, and time-series data. The converter runs in your browser using the native Intl APIs, so conversions are accurate and instant.
This page is statically generated for organic search and enhanced with client-side interactivity for privacy. The tool is useful for quick checks, documentation, QA workflows, and repeat production tasks where copying reliable output matters.
How to use Timestamp Converter
- Paste or enter the source value.
- Adjust the available options for your workflow.
- Review the output and copy it when it is ready.
Key features
- Convert between seconds, milliseconds, and microseconds
- Display in UTC, local time, and any IANA timezone
- Convert ISO 8601 strings to epoch
- Show date math (days from now, days until)
- Detect ambiguous inputs and warn about unit mismatches
- Runs locally with the browser's Intl and Date APIs
Use cases
Debug log timestamps
Convert epoch values in log files into local time to correlate events across services.
Inspect JWT expiration
Decode the exp claim of a JWT and convert it to a readable expiration date.
Validate scheduled jobs
Convert next_run timestamps from cron pickers, Sidekiq, or Temporal into your local timezone.
Audit data exports
Confirm whether a CSV column is seconds or milliseconds before importing into a BI tool.
Sync release timing
Pin release windows in UTC and convert them to the timezones of every team involved.
Usage examples
Timestamp Converter example
Paste or enter your content in the tool workspace.
The generated output is ready to copy, compare, or reuse.
In-depth guide
Seconds, milliseconds, or microseconds?
Different platforms default to different precision. Unix CLI tools use seconds. Java, JavaScript, and many backends use milliseconds. Postgres TIMESTAMP can be microseconds. Mistaking one for another is one of the most common bugs in time handling - off by factors of 1,000 or 1,000,000. When you see an epoch value, count the digits: 10 = seconds, 13 = milliseconds, 16 = microseconds (for any date in this decade).
UTC versus local time
Always store timestamps in UTC. Display them in the user's local timezone. Mixing the two in storage is the root cause of countless bugs around daylight saving time, leap seconds, and ambiguous moments. ISO 8601 with explicit offset (2026-05-22T01:00:00Z) is the safest interchange format.
IANA timezones versus offsets
A fixed offset like -05:00 is ambiguous - is that EST or COT? An IANA timezone name like America/New_York includes the political rules for daylight saving so the same time renders correctly year over year. Always store IANA timezones for human-meaningful schedules (recurring events, business hours), never raw offsets.
Leap seconds and clock drift
POSIX time pretends leap seconds do not exist. In practice, leap seconds occur every few years and are usually smoothed over by NTP. For most applications, this is invisible. For high-precision needs (telemetry, financial trading, scientific data), use a timezone library that handles leap seconds explicitly or rely on monotonic clocks for intervals.
Practical guidance
Use ISO 8601 strings with explicit timezone in APIs and logs. Store UTC in databases. Convert to local time only at the presentation layer. Never use 'naive' (timezone-less) datetimes for storage. If you must work with naive datetimes (legacy systems), document the assumed timezone explicitly in code comments and tests.
Edge cases that bite in production
Daylight saving transitions cause repeated or skipped local times. Pre-1970 dates appear as negative epoch values. Far-future dates may exceed 32-bit signed limits (the 'Year 2038 problem' for legacy systems). Calendar libraries differ on what they consider the start of a week. Birthdays stored as timestamps lose meaning across timezones (a baby born at 11pm in one timezone might 'be born tomorrow' in another). For each of these, the right answer depends on the use case. Document the chosen semantics in code comments and tests. When in doubt, prefer ISO 8601 strings with explicit timezone over raw epoch values - they make the assumption visible.
Building a time-handling style guide
Teams that get bitten by time bugs eventually write a style guide. It typically covers: store UTC, display local, use ISO 8601 in APIs, store IANA timezones for recurring events, prefer monotonic clocks for intervals, never store offset alone. Codify this in lint rules where possible (no use of naive datetimes), and pair with code review checklists for the rest. The timestamp converter helps verify the rules in practice: paste any timestamp in code review, confirm the unit and timezone, and either approve or request changes. Over time, the team internalizes the rules and the converter becomes a quick sanity check rather than a daily tool.
Pro tips
Best practices
Related keywords
timestamp converter, unix timestamp, epoch converter, date time converter.
Frequently asked questions
Is the Timestamp Converter free to use?
Yes. The Timestamp Converter runs in your browser and is designed for quick everyday work without an account.
Does the Timestamp Converter upload my data?
No. Interactive processing happens client-side unless you later connect your own backend or analytics services.
When should I use this tool?
Convert Unix timestamps to readable dates and convert local date-time values back to epoch time.
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