offlineutils
100% offline
Developer
Free · no signup
Updated

Timestamp Converter

A Timestamp Converter translates Unix epoch time in seconds, milliseconds, microseconds or nanoseconds into ISO 8601, RFC 2822, SQL, relative English and any IANA time zone — and back again — using exact integer maths so no digit is lost.

Now—
Try

About Timestamp Converter

Paste a timestamp in any unit, an ISO 8601 or RFC 2822 date, or plain English like "10 days ago", and every representation appears at once. The unit is auto-detected from the digit count and the tool tells you which one it assumed, so a value read as milliseconds instead of seconds is never a silent surprise — and you can override it. Instants are carried as nanoseconds in a BigInt rather than a JavaScript number, which matters more than it sounds: a 19-digit nanosecond timestamp from Go, OpenTelemetry or InfluxDB is already corrupted the moment it touches a double, so converters that divide by a million quietly hand back the wrong digits. Alongside the usual formats you get the wall clock in any IANA zone with that date's real DST offset, ISO week and day-of-year, and the foreign epochs that turn up in forensics and spreadsheets: Windows FILETIME, .NET ticks, Excel serial, Mac HFS+, Apple Cocoa and Julian day.

What Timestamp Converter does

  • Seconds, milliseconds, microseconds and nanoseconds — auto-detected, and it shows you what it detected
  • Exact BigInt maths, so 19-digit nanosecond timestamps keep every digit
  • Plain-English input: now, today, yesterday, '10 days ago', 'in 3 hours'
  • Any IANA time zone with that date's correct DST offset, plus ISO 8601 carrying that offset
  • ISO week, day of year, quarter, leap year and days in month
  • Windows FILETIME, .NET ticks, Excel serial, Mac HFS+, Apple Cocoa and Julian day
  • Warns on the 2038 32-bit overflow, pre-1970 negatives and sub-millisecond truncation

When to reach for Timestamp Converter

  • Decoding a Unix timestamp out of a log line
  • Reading a nanosecond timestamp from Go, OpenTelemetry or InfluxDB, or a microsecond one from Cassandra
  • Working out what a Windows FILETIME or Excel serial date actually means
  • Checking what an incident timestamp was in a colleague's time zone
  • Spotting timezone and DST bugs when an event fires at the wrong wall-clock time

How to use Timestamp Converter

  1. 01

    Paste anything time-shaped

    Enter a Unix timestamp in any unit, an ISO 8601 or RFC 2822 date, or plain English like '10 days ago'.

  2. 02

    Check how it was read

    The line under the input states the unit that was detected. Override it with the 'Read digits as' selector if the guess is wrong.

  3. 03

    Pick a time zone

    Choose any IANA zone to see the wall clock and an ISO 8601 string carrying that zone's offset for that date.

  4. 04

    Copy what you need

    Every row has its own copy button, from Unix nanoseconds to Julian day.

When to use Timestamp Converter vs alternatives

AlternativeUse Timestamp Converter when…Use the alternative when…
`date -d @<ts>` in the terminalyou want every representation at once, in any zone, without remembering flags — and GNU date cannot read a nanosecond epoch directly.you are scripting and need exactly one format on stdout.
epochconverter.comyour timestamp comes from production traffic, or you need microsecond and nanosecond units, foreign epochs, or exact large-integer handling.you want a feature there that we do not have.
Asking an AI chatbotyou need the answer to be arithmetically exact — a language model will happily produce a confident, slightly wrong epoch.you want the concept explained rather than a value converted.

Frequently asked questions

Is my timestamp in seconds, milliseconds, microseconds or nanoseconds?
The digit count gives it away, and the tool applies that rule for you: roughly 10 digits is seconds, 13 is milliseconds, 16 is microseconds and 19 is nanoseconds. Whichever it picks is stated in plain text under the input, and you can override it — a 12-digit value is genuinely ambiguous and you should not have to guess what the tool assumed.
Why do other converters mangle nanosecond timestamps?
Because they use ordinary JavaScript numbers. A double only holds about 15-16 significant digits, so 1753524000123456789 silently becomes 1753524000123456768 before any conversion happens — 21 nanoseconds off, because at that magnitude the nearest representable doubles are 256 apart. This tool parses into a BigInt and never converts to a floating-point number, so the value you paste is the value you get back.
Does it handle dates before 1970?
Yes, and it floors rather than truncates. An instant 1.5 seconds before the epoch sits inside second -2 with a +500 ms remainder, not second -1 — truncating toward zero is a classic off-by-one that puts the result on the wrong side of the epoch.
What is the 2038 problem, and why is it flagged?
A signed 32-bit time_t runs out at 2,147,483,647 seconds, which is 03:14:07 UTC on 19 January 2038. Past that it wraps negative and a system reads the date as 1901. When your value exceeds that limit the tool says so, because the timestamp itself is fine — it is the software receiving it that may not be.
Can it convert Windows FILETIME or Excel dates?
Yes. FILETIME counts 100-nanosecond intervals from 1601-01-01 and .NET ticks count them from 0001-01-01; Excel serial numbers count days from 1899-12-30; Mac HFS+ counts seconds from 1904 and Apple Cocoa from 2001. All of them are shown for any instant you enter, which is exactly what you need when a forensic tool or a spreadsheet hands you a number with no units.
Does the time zone output handle daylight saving?
Yes, per date rather than per zone. The same zone gives a different offset in January and July, and that is what the tool shows — America/New_York resolves to -05:00 in winter and -04:00 in summer, and half-hour and 45-minute zones like Asia/Kolkata and Asia/Kathmandu are handled correctly too.
Is anything uploaded?
No. All of it is integer arithmetic plus the browser's built-in Intl time zone database, running in your tab. Timestamps out of production logs often sit right next to user identifiers, so this is one of the tools where not uploading actually matters.

Related tools

Cron Expression Explainer

Translate cron expressions into plain English and preview the next runs.

UUID Generator

Generate cryptographically random UUIDs (v4) in bulk.

ULID Generator

Generate time-ordered, URL-safe ULIDs in bulk.

Related concepts