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Timestamp Converter Online — Free Unix Epoch, ISO 8601 & Date Converter

Timestamp Converter

Convert between Unix timestamps, ISO 8601, and human-readable dates instantly.

Free online timestamp converter for developers. Paste any timestamp format — Unix epoch (seconds, milliseconds, microseconds, nanoseconds), ISO 8601, RFC 2822, SQL datetime, or human-readable dates — and convert to all formats instantly. Features timezone conversion across 400+ IANA timezones, date math (add/subtract time), duration calculator between two dates, custom format strings, batch conversion, and a live clock. Auto-detects your input format. Runs entirely in your browser — no data is ever sent to a server.

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Tags: timestamp, unix, epoch, date, time, convert, timezone, iso8601, utc

How to Timestamp Converter Online

  1. Paste any timestamp into the input area — Unix epoch (seconds or milliseconds), ISO 8601, RFC 2822, SQL datetime, or a human-readable date like 'May 14, 2024'. The tool auto-detects the format.

  2. View all converted formats instantly on the right panel: Unix seconds, milliseconds, ISO 8601, RFC 2822, human-readable, relative time, and date metadata.

  3. Select a timezone from the dropdown to see the timestamp in any of 400+ IANA timezones. The tool uses your browser's built-in timezone database.

  4. Use Date Math to add or subtract years, months, weeks, days, hours, minutes, or seconds from any timestamp.

  5. Use Duration to calculate the exact time difference between two timestamps, broken down into years, months, days, hours, minutes, and seconds.

  6. Apply a custom format string using tokens like YYYY, MM, DD, HH, mm, ss — or choose from 10 preset formats like ISO 8601, US Date, or Log format.

  7. Click Now (⌘⇧N) to capture the current time in all formats. Copy any output with ⌘⇧C, or share your timestamp via a compressed URL.

Timestamp Converter Features

  • Auto-detection of 12+ input formats: Unix seconds, milliseconds, microseconds, nanoseconds, ISO 8601, ISO 8601 with offset, RFC 2822, SQL datetime, YYYY-MM-DD date-only, natural language dates, and relative expressions.

  • Instant conversion to all output formats simultaneously: Unix epoch (seconds/ms/μs), ISO 8601 (UTC/local/custom timezone), RFC 2822, human-readable, and relative time.

  • 400+ IANA timezone support using the browser's built-in ICU timezone database — no external timezone library needed.

  • Timezone-aware formatting: see any timestamp in UTC, your local timezone, or any selected timezone side by side.

  • Live clock: real-time display of the current timestamp updating every second in all formats.

  • Date math: add or subtract years, months, weeks, days, hours, minutes, or seconds from any parsed timestamp.

  • Duration calculator: compute the exact difference between two timestamps with breakdown into years, months, days, hours, minutes, seconds, and milliseconds.

  • Custom format strings with 20+ tokens: YYYY, MM, DD, HH, hh, mm, ss, SSS, A, Z, dddd, MMMM, X, x, and more.

  • 10 format presets: ISO 8601, US Date, EU Date, Full DateTime, 12-hour, Short, Long, Unix, Sortable, and Log format.

  • Batch conversion: convert multiple timestamps at once, one per line.

  • Date metadata for every timestamp: day of week, day of year, ISO week number, quarter, leap year check, days in month.

  • Period boundaries: start/end of day, month, and year for any timestamp — useful for database queries.

  • Epoch format detection: automatically distinguishes seconds (10 digits), milliseconds (13 digits), microseconds (16 digits), and nanoseconds (19 digits).

  • Relative time display using Intl.RelativeTimeFormat — shows '3 hours ago' or 'in 2 days' with automatic unit selection.

  • Works entirely in your browser — no timestamp data is ever sent to any server. Your data stays completely private.

  • Keyboard shortcuts for power users: ⌘↵ to convert, ⌘⇧N for now, ⌘⇧A for date math, ⌘⇧D for duration, ⌘⇧K to clear.

Frequently Asked Questions

What is a Unix timestamp?
A Unix timestamp (also called epoch time or POSIX time) is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC — known as the Unix epoch. For example, the timestamp 1715629200 represents May 14, 2024, 01:00:00 UTC. Unix timestamps are commonly used in APIs, databases, and log files because they are timezone-independent and easy to sort and compare.
What is the difference between Unix seconds and milliseconds?
Unix seconds is a 10-digit number counting whole seconds since the epoch (e.g. 1715629200). Unix milliseconds is a 13-digit number counting thousandths of a second (e.g. 1715629200000). JavaScript's Date.now() returns milliseconds, while most Unix systems and databases use seconds. This tool auto-detects both formats.
Is this timestamp converter free?
Yes, DevFlow Timestamp Converter is completely free with no usage limits. All conversion, date math, duration calculation, and formatting runs directly in your browser — no account or signup required.
Is my data safe?
All processing happens entirely in your browser using JavaScript. No timestamp data is ever transmitted to a server or stored anywhere outside your browser. Your data stays completely private on your machine.
What is ISO 8601?
ISO 8601 is an international standard for date and time representation. The most common format is YYYY-MM-DDTHH:mm:ss.sssZ, where T separates date and time, and Z indicates UTC. ISO 8601 also supports timezone offsets like +05:30 or -04:00. It is the preferred format for APIs, JSON payloads, and data interchange because it is unambiguous and sortable.
What is RFC 2822 date format?
RFC 2822 is the date format used in email headers and HTTP headers. It follows the pattern: Day, DD Mon YYYY HH:MM:SS +/-HHMM — for example, 'Tue, 14 May 2024 01:00:00 +0000'. While less compact than ISO 8601, it is more human-readable and still widely used in email systems, RSS feeds, and some APIs.
How does timezone conversion work?
The tool uses the browser's built-in Intl.DateTimeFormat API with the IANA timezone database. When you select a timezone like 'America/New_York' or 'Asia/Tokyo', the converter formats the same instant in time using that timezone's UTC offset, including automatic daylight saving time adjustments. No external timezone library is needed — your browser already contains this data.
What is the Year 2038 problem?
The Year 2038 problem affects systems that store Unix timestamps as 32-bit signed integers. The maximum value (2,147,483,647) corresponds to January 19, 2038, 03:14:07 UTC. After this, 32-bit timestamps overflow and wrap to negative values, causing incorrect dates. JavaScript uses 64-bit floating point and is not affected.
How does date math work?
Date math lets you add or subtract a duration from any timestamp. Select a unit (years, months, weeks, days, hours, minutes, seconds) and a value, then choose add or subtract. The result is a new timestamp with all formats recalculated. Month arithmetic handles edge cases like adding 1 month to January 31.
How is duration calculated?
The duration calculator finds the exact difference between two timestamps. It breaks down the result into years, months, days, hours, minutes, seconds, and milliseconds, plus total values in each unit. The calendar-aware calculation accounts for varying month lengths and leap years.
What custom format tokens are supported?
The tool supports 20+ format tokens: YYYY (4-digit year), YY (2-digit), MMMM (full month name), MMM (abbreviated), MM (zero-padded month), DD (zero-padded day), dddd (full weekday), ddd (abbreviated), HH (24h hour), hh (12h hour), mm (minutes), ss (seconds), SSS (milliseconds), A (AM/PM), a (am/pm), X (Unix seconds), x (Unix milliseconds), Z (UTC offset +05:30), ZZ (UTC offset +0530).
Can I convert multiple timestamps at once?
Yes. Switch to Batch mode (⌘⇧B) and enter one timestamp per line. Each line is independently auto-detected and converted, with results displayed showing the input, detected type, and ISO 8601 UTC output.
Does it work offline?
Yes. All conversion logic and timezone data are built into your browser. Once the page has loaded, the Timestamp Converter works without an internet connection.

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