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Unix Timestamp Converter — Convert Unix Time to Date Online Free

100% Private - Processed Locally

Unix Timestamp (Seconds or Milliseconds)

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Processed locally in browser

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Offline· no network access
Human Readable Date (Local & UTC)
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What is the Unix Timestamp Converter?


Unix timestamp to human-readable date — this free Unix time converter translates Unix Epoch timestamps into readable dates and times, and converts dates back into Unix timestamps, all locally in your browser without sending any data to a server. Unix timestamps are fundamental to software development: they appear in server logs, database records, JWT tokens, API responses, cron schedules, file system metadata, and virtually every system that needs to record or compare moments in time.


A Unix timestamp is simply the number of seconds (or milliseconds) elapsed since January 1, 1970 at midnight UTC — the “Unix Epoch.” This single integer provides an unambiguous, timezone-independent representation of any moment in time. However, a number like 1720526400 is not immediately readable to a human, and developers frequently need to convert timestamps to understand what time an event actually occurred, whether a JWT has expired, or what time range a database query covers.


This tool displays both UTC and your local timezone for every timestamp, making it immediately useful regardless of where you are and what timezone your servers operate in. It automatically detects whether your input is in seconds (10 digits) or milliseconds (13 digits), handling both the UNIX standard and the JavaScript Date.now() format without any manual switching.


How to Use the Unix Timestamp Converter


    

  1. Enter a timestamp into the input panel. Paste a 10-digit number for seconds-based Unix time (e.g., 1720526400) or a 13-digit number for milliseconds (e.g., 1720526400000). The tool auto-detects the format.
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  2. The converter instantly displays the corresponding date and time in both UTC and your local timezone. The UTC output is consistent and unambiguous; the local time output reflects your device’s timezone setting.
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  3. To convert a date to a timestamp, enter a date string in ISO 8601 format (e.g., 2024-07-09T00:00:00Z) or a common format like 2024-07-09. The tool returns the corresponding Unix timestamp in both seconds and milliseconds.
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  4. Check JWT expiry: JWT tokens contain an exp claim that is a Unix timestamp. Decode the JWT with our JWT Decoder, copy the exp value, and paste it here to see the exact expiry date and time — instantly knowing whether the token is still valid.
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  5. Use for log analysis: when reviewing server logs with Unix timestamps, paste each timestamp here to understand the exact sequence of events and the time differences between entries, without needing to write a conversion script.
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Common Use Cases


JWT token expiry verification: JSON Web Tokens include exp (expiry), iat (issued at), and nbf (not before) claims as Unix timestamps. When debugging authentication issues — a user is being logged out unexpectedly, or a token is being rejected — paste the exp value here to immediately see the expiry date in human-readable form and determine whether the token has expired.


Database timestamp auditing: Relational and NoSQL databases store creation and update timestamps as Unix integers in many configurations. When querying or reviewing database records for a bug investigation or audit, paste the raw timestamp values here to convert them to readable dates and verify the chronological order of events matches what you expect.


Server log time correlation: Application and server logs that use Unix timestamps for entries can be difficult to read without conversion. Paste individual log timestamps here to understand exactly what time each event occurred in your local timezone, making it easier to correlate events across services that may be in different timezones.


API request and response debugging: REST APIs frequently use Unix timestamps in request parameters (for filtering by date range) and response fields (for event times, rate limit reset times, and resource creation dates). Converting these values here helps you understand the time semantics of API calls when debugging integration issues.


Rate limit reset timing: Many APIs include a rate limit reset timestamp in their response headers (like X-RateLimit-Reset). Paste the reset timestamp here to see exactly when your rate limit will reset and plan your request retry logic accordingly.


How Browser-Only Processing Works for This Tool


Timestamp conversion uses JavaScript’s built-in Date object, which is available in every browser and JavaScript runtime. When you enter a number, the tool constructs a Date object with new Date(timestamp * 1000) (for seconds) or new Date(timestamp) (for milliseconds). It then calls date.toUTCString() for the UTC representation and date.toLocaleString() with your browser’s timezone settings for the local time representation.


The toLocaleString() method uses your operating system’s timezone data, available to the browser through the Intl API — no server-side timezone database lookup is required. The entire conversion happens synchronously, within a single JavaScript expression, with no network access.


Verify this by opening DevTools (F12), going to the Network tab, and converting a timestamp. You will see zero outbound network requests. The conversion is equivalent to typing new Date(1720526400000).toLocaleString() in your browser’s console.


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, at 00:00:00 UTC — a reference point known as the Unix Epoch. Unix timestamps are used universally in computing as a simple, unambiguous way to represent a moment in time independent of timezone. They appear in server logs, database records, API responses, JWT expiry fields, and virtually every modern software system.
Does this handle milliseconds?▼
Yes, the tool automatically detects whether your input is in seconds or milliseconds based on the length of the number. A 10-digit number is treated as seconds (standard Unix time), while a 13-digit number is treated as milliseconds (JavaScript's Date.now() format and many database systems). You can also manually input either format — the tool correctly interprets both.
Are timezone conversions done locally?▼
Yes. The tool uses your browser's local timezone settings via JavaScript's Intl API to generate the 'Local Time' output, and simultaneously provides the standard UTC representation. No server is involved in the timezone calculation — your system timezone is read directly from the browser environment, meaning the local time shown is exactly what your device's clock would show for that timestamp.
Can I convert a human-readable date back to a Unix timestamp?▼
Yes. The tool supports bidirectional conversion. Enter a Unix timestamp to get the human-readable date, or enter a date string (in ISO 8601 format or common date formats) to get the Unix timestamp in both seconds and milliseconds. This is useful for constructing JWT expiry claims, database query parameters, or API request filters that require timestamp ranges.
Why do Unix timestamps matter for developers?▼
Unix timestamps provide a single, unambiguous number to represent any moment in time, independent of timezone, locale, or date format conventions. Databases store timestamps as integers for efficiency. JWTs use the exp claim as a Unix timestamp. Server logs record events with Unix timestamps for precise ordering. APIs use timestamps for pagination cursors and rate limit reset times. Knowing how to read and convert these timestamps is a fundamental developer skill.