Unix Timestamp Converter
Convert Unix timestamps to human-readable dates, or dates back to timestamps, instantly in your browser — auto-detects seconds vs. milliseconds and which direction you need.
What Is a Unix Timestamp?
A Unix timestamp (or "epoch time") is a single number representing a moment in time: the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. Many systems use milliseconds instead of seconds for extra precision, which is the same idea, just multiplied by 1,000.
It's a compact, timezone-free way to store a date — no parsing ambiguity, no locale formatting differences, just one number that means exactly one instant everywhere in the world.
Why Use Unix Timestamps?
Storing a date as a single integer avoids the headaches of string date formats (is 01/02/2024 January 2nd or February 1st?) and sidesteps timezone confusion entirely, since a timestamp is always relative to UTC. Databases, APIs, and logs favor them for exactly this reason — they're unambiguous and easy to sort, compare, and do arithmetic on.
How This Tool Works
Paste one or more timestamps or dates, one per line, and click Convert. This tool detects whether each line is a timestamp (auto-distinguishing seconds from milliseconds) or a date string, then shows every common representation — Unix seconds, Unix milliseconds, ISO 8601, UTC, and your local time. Everything runs in your browser; nothing is uploaded to any server.
Unix Timestamp vs. Human-Readable Date
| Feature | Unix Timestamp | Human-Readable Date (e.g. ISO 8601) |
|---|---|---|
| Format | A single integer | A formatted string |
| Timezone handling | Always UTC-relative, unambiguous | Depends on format — may need an explicit offset |
| Easy to sort/compare | Yes (just compare numbers) | Only if formats match exactly |
| Human readable | No | Yes |
| Common uses | Databases, APIs, logs, git log timestamps | UI display, documents, human communication |
Use a Unix Timestamp When
- Storing a date in a database column or passing it through an API
- You need to sort, compare, or do arithmetic on dates efficiently
- Timezone ambiguity would otherwise be a problem
Use a Human-Readable Date When
- Displaying a date to a person in a UI or document
- Writing a date into a config file, email, or log message meant to be read directly
Common Scenarios for Converting Unix Timestamps
Debugging an API Response or Database Row
APIs and databases commonly store created_at or updated_at fields as raw Unix timestamps. Pasting one here instantly tells you what date and time it actually represents, without writing a script.
Reading a JWT's Expiration Claim
JSON Web Tokens encode exp (expiration) and iat (issued-at) as Unix timestamps. After decoding a token with our JWT Decoder, paste those numeric claim values here to see the actual expiration date.
Naming or Sorting Exported Files by Date
When batch-exporting files — for example, a set of documents converted with our DOCX to PDF tool — naming each one with a timestamp keeps them sortable and avoids collisions. Converting a timestamp back to a readable date confirms the naming is correct.
Checking Log Timestamps Across Time Zones
Server logs often record events in Unix time or UTC. Converting to your local time zone here makes it easy to line up a logged event with when it actually happened for you.
Verifying a Cache or Token Expiration Time
If a cache entry or session token expires at a given timestamp, converting it to a readable date confirms exactly when that will happen, without doing the math by hand.
Other Ways to Convert a Unix Timestamp
You can also convert a Unix timestamp using your command line (for example, date -d @1700000000 on Linux), or a quick snippet in your language of choice. FileCast is useful for a quick, one-off conversion with both directions in one place.
Frequently Asked Questions
Is my data uploaded anywhere?
No. Every conversion happens entirely in your browser — nothing is sent to any server.
How does the tool know if my number is in seconds or milliseconds?
It checks the magnitude: any value of 1,000,000,000,000 (10^12) or more is treated as milliseconds, since a seconds-based timestamp wouldn't reach that many digits until the year 33658. Values below that threshold are treated as seconds.
Can I convert a date string, not just a numeric timestamp?
Yes. If a line isn't all digits, the tool tries to parse it as a date (ISO 8601 formats like 2024-01-15T12:00:00Z work reliably; many other common formats work too, depending on your browser).
What does "Local" mean in the output?
It's the date and time in your device's own time zone setting, computed by your browser — the same time zone your operating system clock uses. It'll show a different value for two visitors in different time zones converting the same timestamp.
Can I convert multiple timestamps at once?
Yes — put each timestamp or date on its own line, and every line is converted in one pass.