Python Snippets

Python Unix Timestamp Snippets

Python examples for current Unix time, timestamp-to-datetime conversion, UTC handling, milliseconds, and formatted date output using the standard library.

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Current Unix timestamp (seconds)

import time
int(time.time())

Current Unix timestamp (milliseconds)

import time
int(time.time() * 1000)

datetime from timestamp (local)

import datetime
datetime.datetime.fromtimestamp(1700000000)

datetime from timestamp (UTC)

import datetime
datetime.datetime.utcfromtimestamp(1700000000)
# Python 3.2+:
datetime.datetime.fromtimestamp(1700000000, tz=datetime.timezone.utc)

Formatted string

import datetime
dt = datetime.datetime.fromtimestamp(1700000000)
dt.strftime("%Y-%m-%d %H:%M:%S")

Timestamp from datetime

import datetime
dt = datetime.datetime(2023, 11, 15, 6, 13, 20, tzinfo=datetime.timezone.utc)
int(dt.timestamp())

Python timestamp basics

Python's time.time() returns seconds since the Unix epoch as a floating-point number. Wrap it with int() for whole Unix seconds, or multiply by 1000 when you need milliseconds.

Timezone-aware datetime output

Use datetime.fromtimestamp(ts, tz=datetime.timezone.utc) for explicit UTC output. Avoid relying on the server's local timezone when generating values for logs, APIs, or database rows.

Python production notes

Python makes it easy to create both naive and timezone-aware datetime values, so be deliberate about which one crosses a system boundary. Use timezone-aware UTC datetimes for APIs, scheduled jobs, and database writes. Convert to a local timezone only for display, reports, or business rules that explicitly depend on a local calendar.

Use int(time.time()) for whole Unix seconds in scripts and command-line tools
Use int(time.time() * 1000) only when the receiving system expects milliseconds
Use datetime.fromtimestamp(ts, tz=timezone.utc) instead of local fromtimestamp for portable output
Use .isoformat() when you need a readable UTC value in logs or JSON

Datetime today in Python: datetime.today() vs datetime.now()

Common Python searches "datetime today python", "today timestamp python", or "datetime now python utc" are answered by the datetime module. datetime.today() and datetime.now() are nearly identical — both return a naive local datetime. For modern code prefer datetime.now(timezone.utc) which returns a timezone-aware UTC value that can be safely converted to a Unix timestamp.

datetime.today() → naive datetime in local timezone (no tzinfo attached)
datetime.now() → same as today() unless you pass a tz argument
datetime.now(timezone.utc) → timezone-aware UTC datetime (preferred for new code)
datetime.now(timezone.utc).timestamp() → current Unix epoch seconds as float
date.today() → today's date with no time component (a date object, not datetime)
int(time.time()) → current Unix seconds as int — the shortest form
time.time_ns() → current epoch nanoseconds (Python 3.7+)

String to datetime in Python, datetime to string

Python users searching "string to datetime python", "py datetime to string", or "datetime to string" want strptime/strftime or datetime.fromisoformat(). Use fromisoformat() for ISO 8601 input (Python 3.7+; 3.11 supports full ISO 8601 including UTC offset).

String to datetime python: datetime.fromisoformat('2024-03-15T14:30:00+00:00') — preferred for ISO 8601
String to datetime python (custom format): datetime.strptime('2024-03-15 14:30:00', '%Y-%m-%d %H:%M:%S')
Py datetime to string / datetime to string: dt.isoformat() returns '2024-03-15T14:30:00+00:00'
Py datetime to string (custom): dt.strftime('%Y-%m-%d %H:%M:%S') returns '2024-03-15 14:30:00'
ISO 8601 round-trip: datetime.fromisoformat(s).isoformat() — produces same string back
For Unix timestamp: dt.timestamp() (seconds float); int(dt.timestamp()) for whole seconds
Python convert string to date / python convert string to date / convert string to date — datetime.fromisoformat(s) for ISO 8601; datetime.strptime(s, fmt) for custom formats
Python date-only output: date.fromisoformat('2024-03-15') returns a date object (no time)

FAQ

Does time.time() return an integer?: No. It returns seconds as a floating-point value. Wrap it with int() for whole Unix seconds, or multiply before rounding when you need milliseconds.
Should datetime values be naive or timezone-aware?: Use timezone-aware UTC datetime values for APIs, databases, and logs. Naive datetime values are best avoided at system boundaries because their timezone meaning is implicit.