All conversion runs locally in your browser — nothing is sent to a server.
What is a Unix Timestamp?
A Unix timestamp (also called epoch time) is the number of seconds that have elapsed since 1970-01-01 00:00:00 UTC, ignoring leap seconds. It's the universal way computers record a single moment in time, free from timezone and calendar quirks. APIs, databases, log files and JWT tokens use it everywhere — sometimes in seconds (10 digits like 1747275600), sometimes in milliseconds (13 digits like 1747275600000) or microseconds (16 digits). DevFormatLab's Timestamp Converter parses any of these, plus regular date strings (ISO 8601, RFC 2822, locale formats), and instantly displays the moment in every common representation across the timezone you choose.
Features
- Auto-detects seconds vs. milliseconds (configurable)
- Parses ISO 8601, RFC 2822 and most browser-recognized date strings
- Outputs Unix seconds, milliseconds, ISO 8601 in UTC and your timezone
- Human-readable date in UTC and any IANA timezone (Asia/Tokyo, America/New_York, …)
- Day of week, day of year, ISO week number and relative-time (e.g. "3 hours ago")
- "Now" button — copy the current epoch in one click
- Per-row copy buttons; 100% browser-only, no tracking
How to use
- Type or paste a Unix timestamp (seconds or milliseconds) or a date string into the input.
- Optionally pick a unit (Auto / Seconds / Milliseconds) — Auto switches at the 1e12 magnitude boundary.
- Pick a timezone (your local timezone, UTC, or one of the popular IANA zones).
- Read every common representation in the results panel; click Copy on any row.
Frequently Asked Questions
Why does the same timestamp show different times in different timezones?
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A Unix timestamp identifies a single moment in time globally. Different timezones simply name that same instant differently — for example 1747275600 is 2026-05-15 03:00 UTC, 12:00 in Tokyo (UTC+9), and 23:00 the previous day in New York (UTC-4 with DST).
How do I know if my timestamp is in seconds or milliseconds?
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A 10-digit value (~1.7 billion in 2026) is almost always seconds. A 13-digit value (~1.7 trillion) is milliseconds. Auto mode uses 1e12 as the cutoff, which has been correct since 2001 and stays correct until the year 33658.
Does it support negative timestamps (dates before 1970)?
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Yes. Negative timestamps represent dates before the Unix epoch (1970-01-01 UTC). For example -86400 is 1969-12-31 00:00 UTC.
Is my data uploaded anywhere?
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No. All parsing and formatting runs entirely in your browser using the native Date and Intl.DateTimeFormat APIs.
What date formats are accepted as input?
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Anything the browser's Date constructor accepts: ISO 8601 (2026-05-15T03:00:00Z), RFC 2822 (Fri, 15 May 2026 03:00:00 GMT), and most locale formats. For ambiguous formats prefer ISO 8601.
What about leap seconds and the year-2038 problem?
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Unix time ignores leap seconds by definition. The 2038 problem only affects 32-bit signed integer storage — JavaScript's Number is 64-bit and can safely represent dates billions of years in either direction.
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Canonical: https://devformatlab.com/en/timestamp