Unix Timestamp Converter

What Is a Unix Timestamp Converter?

A Unix timestamp converter changes Unix/epoch timestamps into human-readable dates and converts dates back into Unix time. It can display the same instant in seconds, milliseconds, UTC, local time, and ISO 8601 format.

How to Convert a Unix Timestamp to a Date

1. Choose Timestamp → Date and enter the number.
2. Leave Auto detect on, or pick seconds, milliseconds, microseconds, or nanoseconds.
3. Select UTC, browser local, or another IANA timezone for the clock display.
4. Read local time, UTC, ISO 8601, seconds, and milliseconds.
5. Copy the value you need. To go the other way, use Date → Timestamp with YYYY-MM-DD, time, and timezone.

Unix Timestamp Examples

• 1700000000 seconds. UTC 2023-11-14 22:13:20 UTC. ISO 8601 2023-11-14T22:13:20.000Z. Milliseconds 1700000000000.
• 1700000000000 milliseconds. Same instant as the seconds value above. JavaScript Date.now() uses this unit.
• Unix 0. 1970-01-01T00:00:00.000Z — the Unix epoch.
• API or log field. A JSON created_at: 1700000000 is the same instant. Format the payload in the JSON Formatter if you need to find the field first.
• JWT exp. A claim of 1700003600 is 2023-11-14T23:13:20.000Z. Decode a full token with the JWT Decoder.

Unix Timestamp in Seconds vs Milliseconds

Contemporary Unix seconds are usually 10 digits. Unix milliseconds are usually 13. That is a practical heuristic, not a law — the converter also checks whether the resulting year is plausible and lets you override the unit. Treating milliseconds as seconds typically jumps the date into the year 50,000 range.

How Unix Timestamps Handle UTC and Time Zones

A Unix timestamp is an instant. UTC and local time only change the wall clock. 1700000000 is always 2023-11-14T22:13:20.000Z. In America/New_York that same instant is an earlier clock time. Use the Time Zone Converter if you already know the instant and only need another region’s clock.

How to Convert a Timestamp to ISO 8601

Unix 1700000000 becomes 2023-11-14T22:13:20.000Z. ISO 8601 is useful in logs and JSON. Unix seconds are useful for storage, sorting, and API filters. Date → Timestamp also accepts an ISO string ending in Z or an offset.

How to Convert a Date to a Unix Timestamp

Enter YYYY-MM-DD and HH:mm:ss, then choose whether that clock time is UTC, your browser local zone, or another IANA zone. The tool does not use browser-specific parsing of “November 14, 2023” as the primary path. To shift a calendar date by days, use the Date Calculator.

Common Developer Use Cases

• API responses and webhooks that return created_at as an integer.
• Application and database logs that print epoch seconds.
• JWT exp and iat claims.
• Analytics events, scheduled jobs, and frontend/backend time checks.

Unix Timestamp Formula

• Unix seconds → date: new Date(timestamp * 1000)
• Unix milliseconds → date: new Date(timestamp)
• Date → Unix seconds: Math.floor(date.getTime() / 1000)
• Date → Unix milliseconds: date.getTime()
• Epoch: 1970-01-01 00:00:00 UTC

Unix time is commonly used by APIs, databases, logs, programming languages, analytics systems, and distributed systems. Not every store uses it.

Common Unix Timestamp Mistakes

• Reading milliseconds as seconds (or the reverse).
• Assuming timezone conversion changes the Unix number — it does not.
• Parsing ambiguous local date strings in different browsers.
• Treating a negative timestamp as invalid instead of a pre-1970 date.
• Showing raw timestamps to end users.
• Forgetting DST when a wall-clock hour repeats or is skipped.

Current Unix Timestamp

The live seconds and milliseconds above the converter come from Date.now() in this browser. They are not fetched from a time API.

What Is the Year 2038 Problem?

Signed 32-bit Unix time overflows at 2,147,483,647 seconds — 2038-01-19T03:14:07.000Z. Modern 64-bit systems are generally not affected. This browser converter uses JavaScript Date, which is not a 32-bit Unix clock.

Unix Timestamp Code Examples

// JavaScript
Math.floor(Date.now() / 1000)
new Date(1700000000 * 1000).toISOString()

# Python
import time
from datetime import datetime, timezone
int(time.time())
datetime.fromtimestamp(1700000000, tz=timezone.utc).isoformat()

-- SQL
-- PostgreSQL
EXTRACT(EPOCH FROM TIMESTAMPTZ '2023-11-14 22:13:20+00')
TO_TIMESTAMP(1700000000) AT TIME ZONE 'UTC'
-- MySQL
UNIX_TIMESTAMP()
FROM_UNIXTIME(1700000000)

Related Tools

• Time Zone Converter — Compare the same instant across IANA regions.
• Date Calculator — Add or subtract calendar days from a date.
• JWT Decoder — Inspect exp and iat claims inside a full token.
• JSON Formatter — Find created_at or timestamp fields in API JSON.
• Cron Parser — Turn a schedule into upcoming run times.
• Time Calculator — Add or subtract hours and minutes from a clock time.

Frequently Asked Questions

What is a Unix timestamp?

A Unix timestamp is the number of seconds (or, in some systems, milliseconds) since 1970-01-01 00:00:00 UTC.

What is epoch time?

Epoch time is another name for Unix time: an integer count from the Unix epoch. People also say POSIX time.

How do I convert a Unix timestamp to a date?

Paste the integer in Timestamp → Date. For seconds, JavaScript uses new Date(timestamp * 1000). For milliseconds, use new Date(timestamp).

How do I convert a date to a Unix timestamp?

Enter YYYY-MM-DD and time, choose the timezone that clock belongs to, then read Unix seconds or milliseconds.

What is the difference between Unix seconds and milliseconds?

Milliseconds are 1000 times larger. 1700000000 seconds and 1700000000000 milliseconds are the same instant.

How many digits is a Unix timestamp?

Current dates are usually 10 digits in seconds and 13 digits in milliseconds. Digit count is a heuristic; override Auto detect when needed.

Does JavaScript use seconds or milliseconds?

JavaScript Date and Date.now() use milliseconds. Divide by 1000 and floor when an API expects Unix seconds.

How do I convert a Unix timestamp to UTC?

The integer already is UTC. This converter prints the UTC clock and the ISO 8601 string ending in Z.

Why is my timestamp showing the wrong date?

The usual cause is treating milliseconds as seconds. The next causes are displaying the instant in an unexpected timezone or entering a local date without saying which zone it used.

Can Unix timestamps be negative?

Yes. Negative values are dates before 1970-01-01 UTC. −86400 is 1969-12-31T00:00:00.000Z.

What is Unix timestamp 0?

0 is the Unix epoch: 1970-01-01T00:00:00.000Z.

What is the Year 2038 problem?

Signed 32-bit Unix time overflows at 2147483647 seconds, 2038-01-19T03:14:07Z. Modern 64-bit systems are generally not affected.

Can I convert milliseconds to a date?

Yes. Paste a 13-digit value or choose Milliseconds. 1700000000000 is 2023-11-14T22:13:20.000Z.

Is this timestamp converter free?

Yes. It runs in the browser and does not require an account.

Does the converter upload my data?

No. Timestamp and date values stay in your browser during normal use.