Unix Timestamp Converter: How to Convert Between Epoch and Human Date

What is a Unix Timestamp?

A Unix timestamp (also called Epoch time) is the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC — the Unix Epoch.

Right now, the timestamp is roughly 1.8 billion and counting up by one every second.

Why 1970?

Unix was developed at Bell Labs in the late 1960s and early 1970s. January 1, 1970 was chosen as the epoch for simplicity — it's a clean, round date. Ken Thompson and Dennis Ritchie picked it, and the world followed.

When You Encounter Timestamps

Timestamps appear everywhere in development:

The most common mistake? Mixing seconds and milliseconds.

How to Convert Timestamps

Using ToolboxPro

Visit our Timestamp Converter and:

1. Paste a timestamp — it auto-detects seconds vs milliseconds

2. See all formats instantly — UTC, ISO 8601, local time, relative time

3. Pick a date from the calendar — get the timestamp for any date

4. Copy any format with one click

Manual Conversion in Code

// JavaScript — Date.now() returns milliseconds
const ms = Date.now();                       // 1716451200000
const seconds = Math.floor(Date.now() / 1000); // 1716451200

// Convert back
const date = new Date(1716451200000);
console.log(date.toISOString());  // "2026-05-23T00:00:00.000Z"

# Python
import time
import datetime

# Current timestamp
ts = time.time()  # 1716451200.123456

# To datetime
dt = datetime.datetime.fromtimestamp(ts)
print(dt.isoformat())  # "2026-05-23T00:00:00.123456"

# From datetime to timestamp
ts2 = dt.timestamp()

-- PostgreSQL
SELECT EXTRACT(EPOCH FROM NOW());           -- seconds
SELECT EXTRACT(EPOCH FROM NOW()) * 1000;    -- milliseconds
SELECT TO_TIMESTAMP(1716451200);            -- timestamp to datetime

-- MySQL
SELECT UNIX_TIMESTAMP();                    -- seconds
SELECT FROM_UNIXTIME(1716451200);           -- timestamp to datetime

The Year 2038 Problem

On January 19, 2038, 32-bit signed integers will overflow. The timestamp 2147483647 (max 32-bit signed) rolls over to -2147483648, which corresponds to December 1901.

Who's affected: Legacy systems, embedded devices, older databases, 32-bit operating systems.

The fix: Use 64-bit integers (safe for 292 billion years) or unsigned 32-bit (safe until 2106).

Most modern systems already use 64-bit timestamps, but check your embedded devices and legacy databases.

Timezone Handling

Timestamps are always UTC. The conversion to local time is purely display logic:

// Always UTC internally
const utc = new Date("2026-05-23T12:00:00Z");
console.log(utc.getTime());  // Same value everywhere

// Display in any timezone
const tokyo = utc.toLocaleString("en-US", { timeZone: "Asia/Tokyo" });
const nyc = utc.toLocaleString("en-US", { timeZone: "America/New_York" });

Best Practice

Store timestamps as UTC integers in your database. Convert to local time only when displaying to users. This avoids every timezone-related bug.

FAQ

What's the difference between seconds and milliseconds? A factor of 1000. Timestamp 1716451200 (seconds) = May 23, 2026. 1716451200000 (milliseconds) = the same moment. Divide by 1000 to convert milliseconds to seconds.

Does a timestamp include timezone? No — timestamps are always UTC. The number itself represents the same instant everywhere on Earth.

How do I get the current timestamp in a shell script?

# Seconds
date +%s

# Milliseconds
echo $(($(date +%s%N)/1000000))

What is ISO 8601? A date format like 2026-05-23T14:30:00+08:00. It's human-readable and includes timezone offset. Our tool shows both formats.