Free Timestamp Converter
Convert Unix timestamps to readable dates and back. Auto-detects seconds vs milliseconds, shows ISO 8601, UTC and local time, and converts whole batches of timestamps at once — all in your browser.
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Enter a timestamp or date to see every representationDate API. Your data never leaves your device.What Is a Unix Timestamp?
A Unix timestamp — also called epoch time, POSIX time or Unix time — is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. It is a single integer that represents a moment in time, entirely independent of time zone, which makes it the ideal format for storing and comparing dates in software.
Because a Unix timestamp has no time zone, no daylight-saving rules and no calendar quirks, it never needs translating between systems. Server A in Tokyo, server B in London and a browser in New York can all store the same number and mean exactly the same instant. It is only when we display that number that a time zone has to be chosen.
Seconds, milliseconds, microseconds and nanoseconds
The same instant can be written with different numbers of digits depending on the unit used. Getting the unit wrong is the single most common timestamp bug.
| Unit | Digits (current) | Used by |
|---|---|---|
| Seconds | 10 digits (~1.7 billion) | Unix, PHP time(), most APIs |
| Milliseconds | 13 digits | JavaScript Date.now(), Java System.currentTimeMillis() |
| Microseconds | 16 digits | Python time.time_ns() / 1000, some DBs |
| Nanoseconds | 19 digits | Go time.UnixNano(), high-precision systems |
If you treat a value meant to be in seconds as milliseconds, you get a date in early January 1970. If you do the opposite, you get a date tens of thousands of years in the future. Checking the digit count is usually enough to tell which one you have.
UTC vs local time
UTC (Coordinated Universal Time) is the global reference clock, unaffected by geography or daylight saving. Local time is UTC shifted by your current time zone offset — for example UTC+05:30 in India, UTC-08:00 in California, or UTC+00:00 in the UK in winter and UTC+01:00 in summer.
A Unix timestamp always represents the same instant everywhere on Earth. Only its human-readable rendering changes depending on which time zone you use to format it. That is why this tool shows both UTC and local time side by side.
Common formats and when to use them
| Format | Example | Best for |
|---|---|---|
| Unix seconds | 1790000000 | Storage, comparison, arithmetic |
| Unix milliseconds | 1790000000000 | JavaScript, Java, event streams |
| ISO 8601 UTC | 2026-09-27T10:30:00Z | JSON APIs, logs, exchange between systems |
| RFC 2822 | Sat, 27 Sep 2026 10:30:00 GMT | Email headers, HTTP Date |
| Human local | 27 Sep 2026, 4:00 PM | User interfaces, emails, reports |
The Year 2038 problem
Many older systems (including some 32-bit versions of Linux) store Unix timestamps in a signed 32-bit integer. The maximum value it can hold is 2,147,483,647, which corresponds to 03:14:07 UTC on 19 January 2038. One second after that, the value overflows and wraps to a negative number, producing a date around 1901.
Modern systems have moved to 64-bit storage, which will not overflow for roughly 292 billion years — comfortably past any sensible planning horizon. But legacy embedded devices, some databases and older firmware still need auditing before 2038.
Common use cases
Debug API Responses
See what a raw timestamp actually represents in human time.
Database Inspection
Decode created_at, updated_at and event timestamps.
Log Analysis
Convert Unix-epoch log lines into readable local times.
Generate Test Fixtures
Produce the exact timestamps your fixtures need.
Timezone Coordination
Compare the same instant in multiple time zones.
Time Arithmetic
Add or subtract days by working in pure seconds.
Audit Timelines
Sequence events from mixed sources on one timeline.
Learn Time Handling
See how UTC, local time and offsets relate.
Privacy and security
This timestamp converter runs entirely in your browser. All conversion uses the native Date object and the Intl formatting APIs — no server, no network requests. Nothing is uploaded, stored or logged.
Frequently Asked Questions
What is a Unix timestamp?
00:00:00 UTC on 1 January 1970, not counting leap seconds. It is a single integer that represents a moment in time, independent of time zone, which makes it ideal for storing and comparing dates in software.Is this timestamp converter free?
Is my data sent to a server?
Date object and Intl formatting APIs. Nothing is uploaded, stored or transmitted. Your timestamps never leave your device.How does the tool know if a timestamp is in seconds or milliseconds?
What is the difference between UTC and local time?
Why does my timestamp show the wrong date?
What is the Year 2038 problem?
2,147,483,647 — corresponding to 03:14:07 UTC on 19 January 2038. One second later, the value overflows and wraps to a negative number, producing a date around 1901. Modern systems have moved to 64-bit storage, which will not overflow for roughly 292 billion years.What is ISO 8601?
YYYY-MM-DDTHH:MM:SSZ, where T separates the date from the time and Z indicates UTC. It sorts lexicographically (so string comparison works), is unambiguous internationally, and is the format JSON and most modern APIs use. The tool also formats to ISO 8601 with milliseconds and with a numeric time zone offset.Can I convert several timestamps at once?
Does the conversion account for leap seconds?
What formats can I enter as a date?
Date parser accepts: ISO 8601 (2026-09-27T10:30:00Z), RFC 2822 (Sat, 27 Sep 2026 10:30:00 GMT), and most common date strings such as 2026-09-27, 27 September 2026, or 09/27/2026. For predictable results, ISO 8601 is the safest choice because it is unambiguous internationally.