What Is a Unix Timestamp?
A Unix timestamp also called epoch time or POSIX time is a single integer that represents the number of seconds that have elapsed since January 1, 1970, at 00:00:00 UTC. That specific moment in time is called the Unix epoch, and it serves as the universal reference point for time measurement across almost every programming language, database system, and operating system in existence.
As of May 2026, the Unix timestamp is a 10-digit number sitting comfortably above 1,700,000,000. It will not become 11 digits until the year 2286, so you have plenty of runway. Some systems particularly JavaScript and Java work in milliseconds instead of seconds, which makes the timestamp 13 digits long. Knowing which format your system uses is the first thing to check when a timestamp does not convert to the date you expect.
Because it is a plain integer, Unix time is timezone-independent, language-independent, and trivially sortable. You can subtract two timestamps to get the exact elapsed time in seconds between two events. You can compare them with a simple greater-than check. You can store them in a database as an indexed integer and query by time range with maximum performance. These properties are why Unix timestamps remain the default time representation in APIs, log files, JWT tokens, and database schemas decades after their invention.
How to Use This Unix Timestamp Converter
This tool works in both directions and updates results in real time as you type. Here is the full workflow:
Check the current timestamp: The live epoch counter at the top shows you the current Unix timestamp updating every second. Copy it any time you need it.
Convert a timestamp to a date: Paste any Unix timestamp in seconds or milliseconds into the input field. The tool auto-detects the format and outputs the UTC date, your local date, and a relative label like "3 days ago" or "in 2 hours".
Convert a date to a timestamp: Switch to the date-to-timestamp mode, pick your date and time using the calendar picker, and get the corresponding Unix timestamp instantly.
Change the timezone: Use the timezone selector to view the converted date in any timezone. The timestamp itself is always UTC the display adapts to your selection.
Copy the result: Click the copy button next to any output to send it to your clipboard, ready to paste into your code, terminal, or database query.
Key Features
Most timestamp converters online are single-direction, timezone-unaware, and have not been updated in years. This tool was built specifically for the workflows developers actually run into:
Live epoch clock: The current Unix timestamp is always visible and updating in real time. No need to run
Date.now()in the browser console just to get the current epoch.Auto-detects seconds vs milliseconds: Paste a 10-digit or 13-digit timestamp and the tool figures out the format automatically. No toggle, no guessing.
Bidirectional conversion: Convert timestamp to date, or date to timestamp both directions are supported in the same tool without switching pages.
Timezone support: View any converted timestamp in UTC, your local timezone, or any named timezone worldwide.
Relative time output: See how long ago or how far in the future a timestamp is "42 minutes ago" or "in 3 days" which is far more useful than a raw date when debugging logs.
100% client-side: Every conversion runs in your browser. No server requests, no logging, no rate limits. Your timestamps and dates never leave your device.
When Should You Use This Tool?
If you have worked with backend systems, APIs, or databases for any amount of time, you have already encountered Unix timestamps more times than you can count. Here are the exact situations where this converter saves you time:
Debugging API responses: You are reading a JSON payload from an external API and there is a field called created_at: 1716370800. You have no idea what date that is. Paste it here and you see it immediately. If the API response also contains complex nested objects and you need TypeScript types for it, our JSON to TypeScript Interface Converter turns the entire payload into clean, type-safe interfaces in one click.
Reading log files: Application logs almost always use Unix timestamps for performance reasons. When something fails at 1716412345, you need to know if that was 3 AM or 3 PM and how long ago it happened. If your logs also use custom patterns that need regex extraction, our Regex Tester and Debugger lets you build and test the exact pattern to extract timestamps from any log format in real time.
Inspecting JWT tokens: JWT payloads contain iat (issued at) and exp (expires at) fields as Unix timestamps. If a token is failing validation and you suspect it has expired, paste the exp value here to see the exact expiry date and time. For full JWT inspection including signature verification and header decoding, our JWT Decoder and Verifier handles the complete token workflow without sending your token anywhere.
Verifying scheduled job execution: When you need to confirm that a cron job ran at the right time, cross-referencing the log timestamp against your schedule is much easier when you can read what the timestamp actually means in plain English. If you are also building or debugging cron schedules, our Cron Job Expression Generator shows you the next 5 exact UTC run times with plain-English explanations for any cron expression.
Understanding Timestamp Formats You Will Actually Encounter
Not every timestamp you find in the wild is a clean 10-digit Unix second. Here is a practical guide to the formats that show up regularly and how to handle each one:
Unix seconds (10 digits): The standard format. Example:
1716370800. Used by Linux, most databases, Python'stime.time(), and the majority of REST APIs. This tool converts these directly.Unix milliseconds (13 digits): JavaScript's
Date.now()and Java'sSystem.currentTimeMillis()return milliseconds. Example:1716370800000. This tool auto-detects the extra three digits and converts correctly without you needing to divide manually.ISO 8601 strings: Strings like
2026-05-22T09:00:00Zare human-readable but need to be converted to a timestamp for most database and API operations. The date-to-timestamp mode handles this format directly.Negative timestamps: Timestamps before January 1, 1970 are negative. Example:
-86400is December 31, 1969. This is valid and this tool handles it correctly, which many basic converters do not.JWT numeric dates: The
iat,exp, andnbffields in JWT tokens are always Unix seconds, never milliseconds. This is defined in RFC 7519 and is one of the most common sources of timestamp confusion for developers working with authentication systems.
Common Mistakes Developers Make with Unix Timestamps
These are the errors that show up in production with frustrating regularity:
Mixing seconds and milliseconds: The single most common mistake. Storing a JavaScript
Date.now()value in a column your backend treats as seconds results in dates showing up as the year 2525. Always know which unit your system expects before writing a timestamp to storage.Treating local time as UTC: Unix timestamps are always UTC. If you build a timestamp from a local time without accounting for the timezone offset, your stored time will be wrong by your UTC offset. Always work in UTC when constructing timestamps programmatically.
Hardcoding timestamps in tests: Tests that use a hardcoded timestamp for "now" pass today and silently fail weeks later when the hardcoded time becomes a date in the past. Use a relative calculation from the current epoch instead.
Ignoring the Year 2038 problem on 32-bit systems: 32-bit signed integers overflow at timestamp
2147483647January 19, 2038. Systems running on 32-bit signed integer timestamps will fail at that point. Most modern systems use 64-bit integers and are unaffected, but legacy embedded systems and some older databases are still at risk.Not validating timestamp ranges on input: A timestamp of
0means January 1, 1970, which is almost certainly a data entry error rather than intentional data. Validate that incoming timestamps fall within a sensible range for your use case.
Related Developer Tools You Might Need
Timestamps appear constantly across authentication, scheduling, and API workflows. If you found this converter useful, you might also need our JWT Secret Key Generator to create cryptographically secure signing keys for the tokens whose timestamps you are inspecting — or our JWT Decoder and Verifier to inspect the full payload including exp and iat fields. All tools are free, browser-based, and require no account.
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