How to use strptime with milliseconds in Python

The strptime() method from the datetime module in Python helps convert string representations into datetime objects. To include milliseconds while parsing time, the %f format code is used. For example, let's consider we have a timestamp string like this: "15/06/2021 13:30:15.120", the string returns a specific date and time including milliseconds (.120). To work with it in Python, such as comparing times, calculating durations, or formatting, we need to convert it into a datetime object. Here's how to do it:

from datetime import datetime

s = "15/06/2021 13:30:15.120"
format = "%d/%m/%Y %H:%M:%S.%f"

dt_obj = datetime.strptime(s, format)
print(dt_obj)

2021-06-15 13:30:15.120000

Syntax

datetime.strptime(date_string, format_string)

Parameters:

• date_string: The string containing the date and/or time to be parsed.
• format_string: The format that tells Python how to interpret the date_string.

Format Codes for Reference

Here's a short list of useful format codes you might need:

Use %f when you want to include milliseconds or microseconds in your datetime string.

Examples of strptime Method

Example 1: Parsing a Time String with Milliseconds

In this example, we convert a string with milliseconds into a datetime object.

from datetime import datetime

s = "15/06/2021 13:30:15.120"
format = "%d/%m/%Y %H:%M:%S.%f"

obj = datetime.strptime(s, format)

print("date_object =", obj)
print("Type:", type(obj))

date_object = 2021-06-15 13:30:15.120000
Type: <class 'datetime.datetime'>

Explanation: The %f in the format string ensures that .120 gets interpreted as 120000 microseconds (or 0.120 seconds).

Example 2: Convert Current Datetime to String and Back

This shows how to convert the current datetime to a string and then parse it back with milliseconds.

from datetime import datetime

s = str(datetime.now())

print(type(s))

print(datetime.strptime(s, '%Y-%m-%d %H:%M:%S.%f'))

<class 'str'>
2025-04-07 09:43:09.006822

Explanation: We convert the current datetime to a string using str(), then use strptime() with %f to parse the microsecond component.

Example 3: Parsing a Date String with Abbreviated Month and Microseconds

This example shows a string with an abbreviated month name and a full microsecond value.

from datetime import datetime

date = datetime.strptime("17 Oct 2021 15:48:35.525001", "%d %b %Y %H:%M:%S.%f")
print(date)

2021-10-17 15:48:35.525001

Explanation: Here, %b is used to parse the abbreviated month name (Oct), and %f ensures microseconds (525001) are included in the result.