Unix Timestamp Converter — Free Online Tool

What Is Unix Timestamp Converter?

A free online Unix timestamp converter. Transform Unix timestamps (seconds or milliseconds) to readable dates in ISO, local, and UTC formats. Or convert any date/time to a Unix timestamp. Includes a live current timestamp display.

Unix timestamps are the standard way computers represent time — a single integer counting seconds (or milliseconds) since January 1, 1970 UTC. While efficient for machines, these numbers are meaningless to humans without conversion. Unix Timestamp Converter provides bidirectional conversion between Unix timestamps and human-readable dates, supporting both seconds and millisecond precision.

The tool operates in two directions. In Timestamp to Date mode, enter a Unix timestamp (10-digit for seconds or 13-digit for milliseconds) and see the corresponding date in multiple formats simultaneously: ISO 8601 (2024-01-15T10:30:00.000Z), local time (your browser's timezone), UTC time, and a relative format ("3 hours ago" or "in 2 days"). The auto-detection determines whether you entered seconds or milliseconds based on the digit count.

In Date to Timestamp mode, pick a date and time using the date picker, and the tool displays the corresponding Unix timestamp in both seconds and milliseconds. This is useful when you need to generate a timestamp for a specific future event — like scheduling a task or setting an expiration date in a JWT token — or when you need to convert a human-readable date from a log entry back to its timestamp form for querying.

The live current timestamp display updates every second, showing the precise Unix time in both seconds and milliseconds. This is a convenient reference for developers who frequently need the current timestamp for API calls, database queries, or debugging sessions. All conversions happen locally with no network requests.

Real-World Use Cases for Unix Timestamp Converter

Debugging API Logs with Timestamps

Your API logs show errors at Unix timestamp 1705315200. Enter it into the Timestamp to Date mode. The tool shows it is January 15, 2024 at 10:40:00 UTC (or your local time equivalent). Check if any deployment or configuration change occurred around that time to identify the root cause.

Setting an Expiration Date in a JWT Token

You need to generate a JWT that expires in 7 days. Use the Date to Timestamp mode: pick today's date + 7 days in the date picker. The tool returns the Unix timestamp in seconds. Use that value as the exp claim in your JWT payload. Verify the duration by converting the timestamp back to a human date.

Converting Database Timestamps for Reporting

Your database stores all event timestamps as Unix milliseconds (13 digits). Export a set of timestamps from a SQL query and convert each one through the tool to get ISO 8601 dates for a business report. The multiple format output lets you copy the dates in the format that matches your reporting tool requirements.

Why Use Unix Timestamp Converter?

Bidirectional: timestamp to date and date to timestamp
Supports both seconds and milliseconds
Multiple output formats: ISO 8601, local, UTC, relative
Live current timestamp display

How to Use Unix Timestamp Converter — Step by Step

For timestamp to date: enter a Unix timestamp (seconds or ms).

View the formatted date in ISO, local, UTC, and relative formats.

For date to timestamp: pick a date and time.

View and copy the resulting Unix timestamp.

Who Is Unix Timestamp Converter Best For?

API debugging
log analysis
database queries
scheduled tasks

Pro Tips for Unix Timestamp Converter

1Remember the 10-digit vs 13-digit rule: timestamps before 2286 (in seconds) are 10 digits. JavaScript Date.now() returns 13 digits (milliseconds). Most databases store seconds (10 digits).
2The ISO 8601 format (2024-01-15T10:30:00.000Z) is the safest choice for API communication and data interchange because it is timezone-aware and machine-parseable.
3When querying databases with timestamp ranges, convert your human-readable date range to timestamps first. For example, "last 24 hours" = now - 86400 (in seconds) or now - 86400000 (in milliseconds).
4The relative format ("2 hours ago") is useful for quickly assessing how recent an event is. Use it for log analysis to spot recent errors without mental math on absolute timestamps.

Unix Timestamp Converter — Frequently Asked Questions

What is a Unix timestamp?

A Unix timestamp is the number of seconds (or milliseconds) that have elapsed since January 1, 1970 UTC (the Unix Epoch). It is widely used in databases, APIs, and logging systems.

How do I know if my timestamp is in seconds or milliseconds?

Timestamps in seconds are typically 10 digits (e.g., 1700000000), while milliseconds are 13 digits (e.g., 1700000000000). The converter auto-detects based on the digit count.

Can I use these tools with sensitive/proprietary data?

Absolutely. All processing runs locally in your browser with zero server uploads. This makes these tools safe for proprietary code, internal API keys, and confidential data.

Do these tools work offline?

Yes, once the page has loaded, most developer tools continue functioning without an internet connection. This makes them ideal for air-gapped environments or travel.

What browsers are supported?

All modern browsers are supported: Chrome, Firefox, Safari, and Edge. Internet Explorer is not supported. The tools leverage modern JavaScript APIs like Web Crypto, TextEncoder, and BigInt.

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