Unix Timestamp and Epoch in Python

Unix time counts elapsed time from the Unix epoch at 1970-01-01T00:00:00Z. Different ecosystems use different units, so always label whether a value is in seconds, milliseconds, microseconds, or nanoseconds.

Quick Start#

The following example uses the standard Python API or a widely used package for this task.

Quick start#

1from datetime import datetime, timezone2import time34seconds = int(time.time())5milliseconds = time.time_ns() // 1_000_0006print(seconds, milliseconds)78dt = datetime.fromtimestamp(seconds, tz=timezone.utc)9print(dt.isoformat())

Common Operations#

This second pattern covers a common production operation or a safer way to handle real input.

Datetime to epoch#

1dt = datetime(, , , , , tzinfo=timezone.utc)2seconds = int(dt.timestamp())3milliseconds = int(dt.timestamp() * )

Important Notes#

Use timezone-aware datetime objects for application data. Naive datetimes can be interpreted using local timezone rules and create ambiguous conversions.

Best Practices#

1. Treat external input as untrusted and handle parse/validation errors explicitly.
2. Keep encoding, units, formats, and library-specific mapping rules explicit at system boundaries.
3. Add test vectors that cover empty input, Unicode text, malformed input, and representative production data.

References#

• POSIX Seconds Since the Epoch
• Python Documentation