time

Key Features

• Retrieves the current time
• Formats and parses time strings
• Measures elapsed time with high precision
• Pauses execution for a given number of seconds
• Converts between time representations (seconds, tuples, strings)
• Obtains system time in UTC or local time
• Works with monotonic clocks for reliable timing
• Supports sleep with subsecond precision
• Avoids float precision loss with nanosecond-resolution variants such as time.time_ns(), time.perf_counter_ns(), and time.monotonic_ns()

Frequently Used Classes and Functions

Examples

Get the current local time as a readable string:

>>> import time

>>> time.ctime()
'Thu Jul 24 14:58:22 2025'

Pause execution for two seconds:

>>> time.sleep(2)

Format the current time as a string:

>>> time.strftime(
...     "%Y-%m-%d %H:%M:%S", time.localtime()
... )
'2025-07-24 14:58:53'

Measure elapsed time with high precision:

>>> start = time.perf_counter()
>>> time.sleep(1)
>>> end = time.perf_counter()
>>> end - start
1.000123456

Common Use Cases

• Measuring the duration of code execution
• Formatting and displaying the current date and time
• Scheduling tasks or delays at specific intervals
• Converting between different time representations
• Benchmarking and profiling code performance
• Implementing retries with delays
• Creating timeouts or intervals in programs
• Simulating delays in tests, scripts, or teaching examples
• Generating timestamps for logs or filenames

Real-World Example

Suppose you want to measure the execution time of a block of code to optimize performance. Here’s how you can achieve that using the time module:

>>> import time

>>> def long_running_task():
...     time.sleep(2)
...

>>> start = time.perf_counter()
>>> long_running_task()
>>> end = time.perf_counter()
>>> elapsed_time = end - start

>>> print(
...     f"The task took {elapsed_time:.2f} seconds."
... )
The task took 2.00 seconds.

In this example, the time module helps you measure how long a task takes to execute, which is valuable for performance tuning and optimization.

To see why time.perf_counter() is the right clock for this job, watch three clocks time a similar 3-second run, time.sleep(2) followed by one second of CPU work. Click Run to replay it, then check Set system clock back 4 s at 1 s:

Each line plots a clock’s reading minus its start value against real time, and the end - start chips show the final result. time.perf_counter() reports the true 3 s. time.process_time() stays flat during time.sleep(2) and reports 1 s because it only counts CPU time. When the system clock is set back, the dashed time.time() line drops at the 1 s mark and ends at −1 s, so don’t use it to time code.

Related Resources

Course

Mastering Python's Built-in time Module

In this course, you'll learn how to use the Python time module to represent dates and times in your application, manage code execution, and measure performance.

intermediate stdlib

For additional information on related topics, take a look at the following resources:

• How to Get the Current Time in Python (Course)
• Python sleep(): How to Add Time Delays to Your Code (Tutorial)
• Using sleep() to Code a Python Uptime Bot (Course)
• How to Get and Use the Current Time in Python (Tutorial)
• A Beginner’s Guide to the Python time Module (Tutorial)
• Using Python datetime to Work With Dates and Times (Tutorial)
• Python Timer Functions: Three Ways to Monitor Your Code (Tutorial)
• Python time.sleep() (Quiz)
• Using Python's datetime Module (Course)
• Python Timer Functions (Course)