Unix Timestamp Converter

What is Timestamp Converter?

A Unix timestamp is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970 — a moment called the Unix epoch. Because it's a single number in UTC, it's the canonical way to represent 'a moment in time' in databases, logs, and APIs, immune to timezone and DST confusion.

How to convert Unix timestamps

1. 1Paste a timestamp (10-digit seconds or 13-digit milliseconds) — the tool auto-detects the unit.
2. 2The converted date is shown in UTC and in your local timezone.
3. 3To go the other direction, pick a date/time in the calendar; the timestamp appears instantly.
4. 4Switch timezone with the dropdown to see the same instant in different regions.

Use Cases

Code Examples

// seconds
const s = Math.floor(Date.now() / 1000);
// milliseconds
const ms = Date.now();
// from timestamp
const d = new Date(s * 1000);

import time, datetime
s = int(time.time())                      # seconds
ms = int(time.time() * 1000)              # milliseconds
d = datetime.datetime.fromtimestamp(s)

import "time"

s := time.Now().Unix()
ms := time.Now().UnixMilli()
t := time.Unix(s, 0)

-- PostgreSQL
SELECT EXTRACT(EPOCH FROM NOW())::bigint;
-- MySQL
SELECT UNIX_TIMESTAMP();
SELECT FROM_UNIXTIME(1700000000);

Key Concepts

Epoch

The reference point from which time is measured. Unix epoch is 1970-01-01 00:00:00 UTC; other systems use different epochs (Windows FILETIME: 1601, NTP: 1900).

Seconds vs milliseconds

10-digit numbers are seconds; 13-digit numbers are milliseconds. Rule of thumb: JavaScript uses ms (`Date.now()`), most other languages use seconds by default.

ISO 8601

A human- and machine-readable date format (`2024-01-15T12:30:45Z`). Preferred for APIs because it's timezone-explicit.

Year 2038 problem

32-bit signed epoch overflows on 2038-01-19 03:14:07 UTC. Modern systems use 64-bit timestamps and are fine until year 292 billion.

Tips & Best Practices

• ▸Always store timestamps in UTC. Convert to local time only at the presentation layer.
• ▸In JavaScript, `Date.now()` returns milliseconds; the Unix convention is seconds. Divide by 1000 when talking to non-JS systems.
• ▸JWT `exp` and `iat` are always in seconds, per RFC 7519. Passing milliseconds is a common bug.
• ▸Never do timezone math manually. Use `date-fns-tz`, `luxon`, `dayjs/plugin/timezone`, or Python `zoneinfo` — DST rules change and manual offsets go stale.