Add milliseconds to datetime in Python

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Borislav Hadzhiev

Last updated: Jun 22, 2022

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Add milliseconds to datetime in Python #

Use the timedelta() class from the datetime module to add milliseconds to datetime, e.g. result = dt + timedelta(milliseconds=300). The timedelta class can be passed a milliseconds argument and adds the specified number of milliseconds to the datetime.

main.py
from datetime import datetime, timedelta # ✅ parse datetime string and add milliseconds to datetime d = '2023-11-24 09:30:00.000123' # 👇️ convert string to datetime object dt = datetime.strptime(d, '%Y-%m-%d %H:%M:%S.%f') print(dt) # 👉️ 2023-11-24 09:30:00.000123 result_1 = dt + timedelta(milliseconds=300) print(result_1) # 👉️ 2023-11-24 09:30:00.300123 # ----------------------- # ✅ add milliseconds to datetime dt_2 = datetime(2023, 9, 24, 9, 30, 35) print(dt_2) # 👉️ 2023-09-24 09:30:35 result_2 = dt_2 + timedelta(milliseconds=400) print(result_2) # 👉️ 2023-09-24 09:30:35.400000 # ------------------------ # ✅ add milliseconds to current time now = datetime.today() print(now) # 👉️ 2022-06-22 13:42:52.445381 result_3 = now + timedelta(milliseconds=500) print(result_3) # 👉️ 2022-06-22 13:42:52.945381
If you only have a time component, e.g. 09:30:13.000123 scroll down to the last code snippet.

Make sure to import the datetime and timedelta classes from the datetime module.

The first example creates a datetime object from a datetime string and adds milliseconds to it.

main.py
from datetime import datetime, timedelta # ✅ parse datetime string and add milliseconds to datetime d = '2023-11-24 09:30:00.000123' # 👇️ convert string to datetime object dt = datetime.strptime(d, '%Y-%m-%d %H:%M:%S.%f') print(dt) # 👉️ 2023-11-24 09:30:00.000123 result_1 = dt + timedelta(milliseconds=300) print(result_1) # 👉️ 2023-11-24 09:30:00.300123

The datetime.strptime() method returns a datetime object that corresponds to the provided date string, parsed according to the format.

If you have a date string that is formatted in a different way, use this table of the docs to look up the format codes you should pass as the second argument to the strptime() method.

The second example uses the datetime class to create a datetime object and the timedelta class to add milliseconds to it.

main.py
from datetime import datetime, timedelta dt_2 = datetime(2023, 9, 24, 9, 30, 35) print(dt_2) # 👉️ 2023-09-24 09:30:35 result_2 = dt_2 + timedelta(milliseconds=400) print(result_2) # 👉️ 2023-09-24 09:30:35.400000

We passed values for the year, month, day, hour, minute and second arguments.

The third example adds milliseconds to the current time.

main.py
from datetime import datetime, timedelta now = datetime.today() print(now) # 👉️ 2022-06-22 13:42:52.445381 result_3 = now + timedelta(milliseconds=500) print(result_3) # 👉️ 2022-06-22 13:42:52.945381

The datetime.today() method returns the current local datetime.

We need to use a datetime object because it automatically rolls over the seconds, minutes, hours, days, months and years if necessary.

This wouldn't be possible if we only had the time component. For example, 11:59:59.778231 PM + 5000 milliseconds would raise an exception.

If you only have the time component, use the datetime.combine method to combine the time with the current (or some other) date and get a datetime object.
main.py
from datetime import datetime, date, timedelta, time t = time(6, 25, 30, 123) print(t) # 👉️ 06:25:30.000123 result = datetime.combine(date.today(), t) + timedelta(milliseconds=400) print(result) # 👉️ 2022-06-22 06:25:30.400123 only_t = result.time() print(only_t) # 👉️ 06:25:30.400123

The datetime.combine method takes a date and time as arguments and returns a new datetime object by combining them.

Once we get a datetime object, we can use the timedelta class to add milliseconds to it.

Use the time() method on the datetime object if you only need to extract the time after the operation.

main.py
from datetime import datetime, date, timedelta, time t = time(6, 25, 30, 123) print(t) # 👉️ 06:25:30.000123 result = datetime.combine(date.today(), t) + timedelta(milliseconds=400) print(result) # 👉️ 2022-06-22 06:25:30.400123 # ✅ only get updated time only_t = result.time() print(only_t) # 👉️ 06:25:30.400123

The datetime.time method returns a time object with the same hour, minute, second and millisecond.

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