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Unix Timestamp Guide: Convert, Calculate & Understand Epoch Time
2026-06-25 ยท 8 min read
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What Is a Unix Timestamp?
A Unix timestamp counts the number of seconds since January 1, 1970, 00:00:00 UTC - known as the Unix epoch. It is the universal time format used in databases, APIs, log files, and virtually every programming language.
Why is Unix time so popular? Because it is a single integer - no timezones, no daylight saving complications, no ambiguous date formats. 1719360000 represents the exact same moment everywhere on Earth.
Converting Across Programming Languages
- JavaScript -
Date.now()returns milliseconds.Math.floor(Date.now() / 1000)for seconds. - Python -
import time; int(time.time()) - PHP -
time() - SQL -
SELECT UNIX_TIMESTAMP()(MySQL),SELECT EXTRACT(EPOCH FROM NOW())(PostgreSQL)
The Year 2038 Problem
Unix timestamps in signed 32-bit integers max out at January 19, 2038. After that second, the integer overflows to negative, rewinding dates to 1901. Legacy systems still using 32-bit time_t will fail. Most modern systems use 64-bit timestamps.
Common Pitfalls
- Seconds vs milliseconds - If your timestamp has 13 digits, it is in milliseconds. Divide by 1000.
- Timezone confusion - Unix timestamps are always UTC. Apply timezone offset for display only.
- Leap seconds - Unix time ignores leap seconds, pausing or repeating a second to stay synced.
Convert any timestamp now: ToolHub Timestamp Converter.
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