Epoch & Unix Timestamp Converter
Convert Unix/epoch timestamps to human-readable UTC and local dates, and turn any date back into an epoch timestamp. Seconds and milliseconds are detected automatically, and everything runs locally — your data is never uploaded.
Epoch → Date
Paste a Unix timestamp to see the date.
Date → Epoch
Pick a date and time to get its timestamp.
How the epoch converter works
This tool converts between Unix timestamps and calendar dates entirely in your browser. Nothing is sent to a server — the maths is done by JavaScript running on your device, so it is fast, private, and works offline once the page has loaded.
Epoch → Date
Enter a Unix timestamp and the tool figures out whether it is in seconds or
milliseconds, then shows the matching ISO 8601 value, the
UTC time, your local time, and a friendly relative time such as
“3 days ago”. Use the unit buttons to override auto-detection if your data is unusual.
Date → Epoch
Pick a date and time with the picker (or the Use now button) and the tool returns the epoch value in both seconds and milliseconds. The Local time / UTC toggle tells the converter how to interpret the value you entered, which matters whenever timezones are involved.
Auto-detecting the unit
A present-day timestamp is 10 digits in seconds and 13 digits in milliseconds. The converter treats values with 12 or more digits as milliseconds and everything else as seconds, which covers virtually all real-world data while letting you force a unit when needed.
Live timestamp
The banner at the top shows the current Unix time, ticking once per second. Click Copy to grab it, or Use it to drop it straight into the Epoch → Date converter so you can see exactly what “now” looks like as a date.
What is Unix epoch time?
Unix time (also called epoch time or POSIX time) represents a moment as a single number: the count of seconds elapsed since the Unix epoch, which is 00:00:00 UTC on 1 January 1970. Because it is just an integer measured against UTC, it is independent of any timezone and trivial for computers to store, sort, and do arithmetic with.
Why January 1, 1970?
Early Unix engineers needed a fixed reference point to count from. They picked the start of 1970 — close to when Unix was being built — as a convenient, recent round number that kept stored values small on the limited hardware of the day. The choice became a de-facto standard and never changed.
Seconds vs milliseconds
Unix tools, JWTs, and many APIs count in seconds. JavaScript, Java, and a lot of logging stacks count in milliseconds — the same instant, multiplied by 1,000. Multiply seconds by 1,000 to get milliseconds; divide milliseconds by 1,000 to get seconds.
Leap seconds: Unix time deliberately ignores leap seconds and treats every day as exactly 86,400 seconds. That keeps the arithmetic simple, at the cost of not being a perfectly continuous count of physical seconds.
UTC vs local time
An epoch timestamp is an absolute instant — it has no timezone baked in. The timezone only matters when that instant is shown to a human. This converter always displays both views so you can see the difference at a glance.
UTC
Coordinated Universal Time is the global reference clock the epoch is defined against. The UTC value for a given timestamp is the same everywhere on Earth, which is why logs, APIs, and databases almost always store and exchange time in UTC.
Local time
Local time is that same instant shifted by your timezone offset and any daylight saving rules. When you convert a date back to epoch, use the UTC / Local toggle to tell the tool which clock the value you typed belongs to — otherwise the result can be off by hours.
Common uses for epoch timestamps
Epoch time shows up anywhere a system needs to record “when” in a compact, unambiguous, timezone-free way. Here is where IT, security, and development teams meet it most often.
- JWT tokens —
iatandexpare epoch seconds - Log analysis — server and application logs timestamp every line
- SIEM / SOC — security events normalised to epoch for correlation
- APIs — request/response payloads pass time as integers
- AWS & Azure — metrics, billing, and CloudTrail/Activity logs
- Linux & Windows logs — event records and file mtimes
- Databases — timestamp columns and TTL/expiry fields
- Schedulers — cron, queues, and cache expiry use epoch math
Why a number, not a date? A single integer makes “how long between these two events” a simple subtraction, sorting a numeric comparison, and storage compact and unambiguous — all without timezone confusion until the value is shown to a person.
Privacy: processed locally in your browser
Every conversion this tool performs happens entirely in your browser. The timestamps and dates you enter are handled exclusively by JavaScript in your browser tab — never transmitted to a server, never logged, and never stored anywhere outside your device.
Technical verification: open your browser's developer tools (F12), select the Network tab, and convert something. You will see zero outgoing requests — the tool works entirely through in-memory JavaScript.
Frequently asked questions
What is an epoch converter?
An epoch converter translates between Unix epoch timestamps — the number of seconds (or
milliseconds) since 1 January 1970 at 00:00:00 UTC — and human-readable calendar dates. Paste a
timestamp such as 1749680000 and it shows the matching UTC and local date; enter a
date and it returns the corresponding epoch value. This tool does both directions instantly in
your browser.
What is Unix epoch time?
Unix epoch time, also called Unix time or POSIX time, represents a point in time as a single number: the count of seconds since midnight UTC on 1 January 1970. It deliberately ignores leap seconds, so each day is treated as exactly 86,400 seconds. Because it is just a number measured against UTC, it is timezone-independent and easy for computers to store, compare, and calculate with.
Why does Unix time start on January 1, 1970?
The date was chosen by the engineers building early Unix systems as a convenient, recent round number to count from. It was close to when Unix was created, which kept stored values small for the limited hardware of the era. The choice stuck and became a standard, so 1 January 1970 UTC — “the epoch” — is now the reference point used across operating systems, languages, databases, and protocols.
How do I tell seconds from milliseconds?
A present-day timestamp in seconds has 10 digits (for example 1749680000), while the
same instant in milliseconds has 13 digits (1749680000000). This tool auto-detects by
length: values with 12 or more digits are treated as milliseconds, otherwise as seconds. You can
override the guess with the Seconds or Milliseconds buttons if your data uses a different convention.
What is the difference between epoch seconds and milliseconds?
Both count from the same 1970 epoch and differ only in resolution. Seconds-based timestamps (Unix
tools, JWTs, many APIs) tick once per second. Millisecond timestamps (JavaScript's
Date.now(), Java, many logging systems) are 1,000 times larger and resolve to the
thousandth of a second. Multiply seconds by 1,000 for milliseconds, or divide milliseconds by 1,000
for seconds.
What is the difference between UTC and local time?
An epoch timestamp is an absolute instant with no timezone. UTC is the global reference clock the epoch is defined against, so its value is the same for everyone. Local time is that same instant shifted by your timezone offset and daylight saving rules. When converting a date back to epoch, use the UTC/Local toggle to say how the date you entered should be interpreted.
Is my data sent to a server?
No. Every conversion happens entirely in your browser using JavaScript. The values you enter are never transmitted, logged, or stored outside your own browser tab. You can confirm this by opening your browser's Network tab in developer tools — you will see no outgoing requests — and the tool keeps working even if you disconnect from the internet after the page loads.
What is the year 2038 problem?
Older software stores Unix time in a signed 32-bit integer, which maxes out at 2,147,483,647 seconds — reached at 03:14:07 UTC on 19 January 2038. After that the counter overflows to a negative number and misreads the date as 1901. Modern systems use 64-bit integers, which push the limit billions of years out, but some legacy embedded and database systems may still need updating before 2038.
Where are epoch timestamps used?
Epoch time is everywhere: JWT iat/exp fields, server and application
logs, SIEM and SOC event records, AWS and Azure metrics and billing, Linux and Windows event logs,
database timestamp columns, cron and scheduling systems, file modification times, and API
payloads. A single number makes time trivial to sort, compare, and subtract regardless of timezone.
Why do computers use epoch timestamps instead of dates?
A single integer is simpler and more reliable than a structured date with years, months, days, and timezones. Duration becomes basic subtraction, sorting is numeric comparison, and storage is compact and unambiguous. Because the value is defined against UTC, it avoids timezone and daylight saving confusion until the moment it is shown to a human — exactly what this converter does.