How to add Milliseconds to Datetime in Python

# Add milliseconds to datetime in Python

Use the timedelta() class from the datetime module to add milliseconds to datetime.

The timedelta class can be passed a milliseconds argument and adds the specified number of milliseconds to the datetime object.

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from datetime import datetime, timedelta

d = '2023-11-24 09:30:00.000123'

# 👇️ Convert a string to a datetime object
dt = datetime.strptime(d, '%Y-%m-%d %H:%M:%S.%f')

print(dt)  # 👉️ 2023-11-24 09:30:00.000123

result = dt + timedelta(milliseconds=300)
print(result)  # 👉️ 2023-11-24 09:30:00.300123

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

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

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from datetime import datetime, timedelta

d = '2023-11-24 09:30:00.000123'

# 👇️ Convert a string to a datetime object
dt = datetime.strptime(d, '%Y-%m-%d %H:%M:%S.%f')

print(dt)  # 👉️ 2023-11-24 09:30:00.000123

result = dt + timedelta(milliseconds=300)
print(result)  # 👉️ 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.

# Using the datetime class to create a datetime object

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

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from datetime import datetime, timedelta

dt = datetime(2023, 9, 24, 9, 30, 35)
print(dt)  # 👉️ 2023-09-24 09:30:35

result = dt + timedelta(milliseconds=400)
print(result)  # 👉️ 2023-09-24 09:30:35.400000

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

# Adding milliseconds to the current time

If you need to add milliseconds to the current time, use the datetime.today() method to get a datetime object that stores the current time.

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from datetime import datetime, timedelta


now = datetime.today()
print(now)  # 👉️ 2023-07-22 10:38:19.223431

result = now + timedelta(milliseconds=500)
print(result)  # 👉️ 2023-07-22 10:38:19.723431

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

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.

# Using the datetime.combine method to add milliseconds to a time

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.

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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)  # 👉️ 2023-07-22 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.

# Extracting the time component after adding milliseconds to a datetime

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

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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)  # 👉️ 2023-07-22 06:25:30.400123

# ✅ Only get the 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.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• How to add Days or Weeks to a Date in Python
• How to add Hours to Datetime in Python
• How to add Minutes to Datetime in Python
• How to add Months to a Date in Python
• How to add Seconds to Datetime in Python
• How to Add year(s) to a date in Python