What is a Unix timestamp?

A Unix timestamp (also called epoch time) is the number of seconds (or milliseconds) elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. It is a standard way to represent a point in time in programming.

How does the tool know if my timestamp is seconds or milliseconds?

If the number is greater than 9,999,999,999 it is treated as milliseconds (13+ digits). Otherwise it is treated as seconds (10 digits). The detected format is shown in the results row.

What is ISO 8601 format?

ISO 8601 is the international standard for representing date and time. A typical ISO 8601 timestamp looks like 2024-11-14T12:00:00.000Z. The Z suffix indicates UTC.

Can I convert a date in a specific timezone to a Unix timestamp?

Yes. In the Date to Timestamp section, select the desired timezone from the dropdown, enter the date and time, and the tool computes the UTC-equivalent Unix timestamp for that local time.

Why does the live clock tick every second?

The Current Time section updates with a 1-second interval so you can copy the exact current timestamp whenever you need it without having to refresh the page.

What does relative time mean?

Relative time expresses the timestamp as human-readable offset from now: for example "3 days ago" or "in 2 hours". It is useful for quickly understanding how far in the past or future a timestamp is.

Is there a limit on how old or far in the future a timestamp can be?

The tool uses JavaScript's Date object, which supports dates from approximately 271,821 BCE to 275,760 CE. Any Unix timestamp within that range will convert correctly.

Can I convert a negative Unix timestamp (dates before 1970)?

Yes. Negative Unix timestamps represent dates before 1 January 1970 UTC. Enter a negative number and the tool will convert it to the correct historical date.

How do I get the current Unix timestamp in JavaScript?

Use Math.floor(Date.now() / 1000) for seconds or Date.now() for milliseconds. The live Current Time section at the top of this tool shows both values updating in real time so you can copy the exact timestamp for any moment.

What is the Unix timestamp for midnight on a specific date?

Use the Date to Timestamp section: select the date, set the time to 00:00, choose the timezone (UTC for midnight UTC or your local zone for local midnight), and copy the resulting Unix timestamp in seconds.

Unix Timestamp Converter

Convert Unix timestamps to human-readable dates and vice versa. Auto-detects seconds vs milliseconds.

Current Time

Unix (seconds)

1783918896

Unix (milliseconds)

1783918896312

ISO 8601

2026-07-13T05:01:36.312Z

UTC String

Mon, 13 Jul 2026 05:01:36 GMT

Timestamp → Date

Enter a timestamp above to see formatted dates

Date → Timestamp

Select a date and time to see the timestamp

A timestamp converter is a tool that translates Unix timestamps, the number of seconds elapsed since 1 January 1970, into human-readable dates and times, and vice versa. Developers use timestamp converters when debugging logs, working with database records, or inspecting API responses that store dates as numbers rather than formatted strings. AlteredIdea's timestamp converter runs entirely in your browser: no timestamp or date value is sent to any server.

Free online Unix timestamp converter: epoch to date and back

Unix timestamps appear everywhere in software: database records, log files, API responses, JWT claims, and analytics events. Reading a number like 1700000000 and knowing it means Thu Nov 09 2023 01:53:20 UTC is not intuitive. This tool converts any epoch timestamp to a human-readable date in multiple formats and timezones instantly.

The timezone breakdown section is particularly useful when working across distributed teams: convert a timestamp once and see its equivalent in New York, London, Dubai, Tokyo, and other major zones side by side. The reverse converter lets you go from a calendar date in any timezone back to its Unix timestamp, eliminating manual timezone arithmetic.

Step-by-step guide

1
View the current time
The top section shows the live current Unix timestamp in seconds and milliseconds, updating every second, along with the ISO 8601 and UTC string representations.
2
Convert a timestamp to a date
Paste any Unix timestamp (seconds or milliseconds) into the Timestamp input box. The tool auto-detects which format it is.
3
Read the converted date
ISO 8601, UTC, local time, relative time, and the detected format all appear as rows below the input with individual Copy buttons.
4
Check the timezone breakdown
Scroll to the Timezone Breakdown section to see the timestamp expressed in UTC, New York, London, Dubai, Tokyo, and other major zones.
5
Convert a date to a timestamp
Use the Date to Timestamp section: pick a date, optionally a time, select a timezone, and get the corresponding Unix timestamp in seconds and milliseconds.

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Frequently Asked Questions

What is a Unix timestamp?: A Unix timestamp (also called epoch time) is the number of seconds (or milliseconds) elapsed since 00:00:00 UTC on 1 January 1970, not counting leap seconds. It is a standard way to represent a point in time in programming.
How does the tool know if my timestamp is seconds or milliseconds?: If the number is greater than 9,999,999,999 it is treated as milliseconds (13+ digits). Otherwise it is treated as seconds (10 digits). The detected format is shown in the results row.
What is ISO 8601 format?: ISO 8601 is the international standard for representing date and time. A typical ISO 8601 timestamp looks like 2024-11-14T12:00:00.000Z. The Z suffix indicates UTC.
Can I convert a date in a specific timezone to a Unix timestamp?: Yes. In the Date to Timestamp section, select the desired timezone from the dropdown, enter the date and time, and the tool computes the UTC-equivalent Unix timestamp for that local time.
Why does the live clock tick every second?: The Current Time section updates with a 1-second interval so you can copy the exact current timestamp whenever you need it without having to refresh the page.
What does relative time mean?: Relative time expresses the timestamp as human-readable offset from now: for example "3 days ago" or "in 2 hours". It is useful for quickly understanding how far in the past or future a timestamp is.
Is there a limit on how old or far in the future a timestamp can be?: The tool uses JavaScript's Date object, which supports dates from approximately 271,821 BCE to 275,760 CE. Any Unix timestamp within that range will convert correctly.
Can I convert a negative Unix timestamp (dates before 1970)?: Yes. Negative Unix timestamps represent dates before 1 January 1970 UTC. Enter a negative number and the tool will convert it to the correct historical date.
How do I get the current Unix timestamp in JavaScript?: Use Math.floor(Date.now() / 1000) for seconds or Date.now() for milliseconds. The live Current Time section at the top of this tool shows both values updating in real time so you can copy the exact timestamp for any moment.
What is the Unix timestamp for midnight on a specific date?: Use the Date to Timestamp section: select the date, set the time to 00:00, choose the timezone (UTC for midnight UTC or your local zone for local midnight), and copy the resulting Unix timestamp in seconds.

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