What Timestamp Converter helps you do

Convert Unix timestamps to readable dates and back. A numeric value below one trillion is treated as seconds and a larger one as milliseconds, then shown in UTC, the browser's local time and ISO 8601. There is no time zone selector; local means the device's current zone.

Conversions run in your browser. No timestamps are sent to Haivix.

How it works

These tools transform text locally: they parse, format, encode or render a string in your browser. Nothing you paste is uploaded to Haivix, but some tools load a library from a public CDN, so the page needs a network connection and your browser makes that request. The transformations operate on syntax, not meaning: a formatter can make invalid code look tidy, an encoder can hide a value without protecting it, and a preview can render markup that was never meant to execute. Outputs are exact strings, which means line endings, byte order marks and character encoding all matter when you paste the result somewhere else.

How to use Timestamp Converter

Paste a timestamp, or type a date string.
Choose timestamp to date, or date to timestamp.
Read the UTC, local and ISO representations.
Copy the value your system expects.

When to use it

Decode a Unix timestamp from a log or API response.
Generate an epoch value to hard-code into a test.
Check what a timestamp means in UTC and in local time.
Compare seconds and milliseconds for the same moment.
Turn a date from a form into an epoch value.
Sanity-check a token expiry before debugging it.

When not to use it

Do not use it to convert between named time zones; it shows UTC and the device zone only.
Do not expect leap-second handling or historical zone rules.
Do not rely on ambiguous date strings without checking the parsed result.

Example

The timestamp 1700000000 corresponds to late November 2023 in UTC, and 1700000000000 is the same moment in milliseconds. A date-only string such as 2024-01-15 is parsed as UTC midnight by the ISO rules, while a string with a time and no zone is interpreted as local time. The local row reflects the device, not a chosen region.

What you can do with Timestamp Converter

Convert a Unix timestamp to UTC, local and ISO dates.
Convert a date string to seconds and milliseconds.
Detect seconds versus milliseconds by magnitude.
Fill the current time with one click.
Show both second and millisecond values.
Run the conversion locally in the browser.

Example: test with a real sample before trusting the output

Keep the original text. These tools produce a new value rather than editing in place, so a bad transform is reversible only if you still have the source.

Test with a representative sample, including the awkward case: a quote inside a string, a tag inside an attribute, a newline in the middle of a value.

Check line endings and encoding when moving between Windows, Unix and a browser form. A trailing carriage return can break a signature or a hash.

Treat pasted HTML and Markdown as untrusted. A preview that renders raw markup can execute event handlers even when it looks harmless.

Verify the result with the real parser, compiler or linter before shipping. A browser-side formatter is a convenience, not a substitute for the toolchain.

Prefer exact values over screenshots or copied rendered text. Rendering can normalize quotes, dashes and spaces in ways that break the next tool in the chain.

What to know before you start

Unix time has no inherent time zone, so the displayed zone is your choice, not part of the value.
Leap seconds are not represented, matching standard Unix time behaviour.
There is no named time zone selector; it uses UTC and the browser's local zone.
Date parsing of non-ISO strings follows browser behaviour and can vary.

Common mistakes

Assuming local time means a specific city.
Mixing seconds and milliseconds in the same system.
Passing a date string in a non-ISO format and expecting a stable parse.
Forgetting that the tool shows the device zone, not the server zone.

Troubleshooting

If nothing happens, the input may not parse as a number or a date.

If the year is wrong by decades, the value may be in milliseconds when seconds were expected.

If the local and UTC rows differ, that is the device's offset at that date.

If a date string fails, use an ISO form such as 2024-01-15T10:00:00Z.

Timestamp Converter