How to measure time with high-precision in Python?

Python provides various modules, such as time, datetime, and timeit, to measure time with high accuracy. These modules offer high-resolution clocks to measure time intervals.

The following are several methods used to measure time with high precision in Python.

• Using time.time() Method
• Using time.perf_counter() Function
• Using timeit.default_timer()

Using time.time() Method for Simple Timing

The time.time() method returns the current time in seconds since the epoch as a floating-point number. The epoch is system-dependent, but on Unix-like systems, it is typically January 1, 1970, 00:00:00 (UTC).

Example

The following program measures the time taken to execute a loop that multiplies numbers. It uses time.time() to capture the start and end times, then prints the total elapsed time in seconds:

import time

start = time.time()
for i in range(1000000):
    _ = i * 2
end = time.time()

print("Time taken:", end - start, "seconds")

Following is the output of the above code:

Time taken: 0.09123420715332031 seconds

Using time.perf_counter() Function

The time.perf_counter() function is used to measure short durations. It provides the highest available resolution timer and also includes time elapsed even when the local system is in sleep.

Example

The following program measures the execution time using time.perf_counter() function. It records the start and end times of a loop that performs a simple multiplication operation (1 million times), then calculates and prints the elapsed time with high precision:

import time

start = time.perf_counter()
for i in range(1000000):
    _ = i * 2
end = time.perf_counter()
print("High precision time taken:", end - start, "seconds")

Following is the output of the above code:

High precision time taken: 0.087654321 seconds

Using timeit.default_timer()

The default_timer() function is defined in Python's timeit module. This function is used for precise time measurements. It selects the most accurate timer available on your system (e.g., time.perf_counter() or time.time()) based on the platform.

Example

In the following program, we are measuring the precise execution time of a loop by using timeit.default_timer() function. The 'start' records the beginning time, 'end' captures the end, and their difference gives the high-precision duration in seconds:

from timeit import default_timer as timer

start = timer()
for i in range(1000000):
    _ = i * 2
end = timer()
print("Time measured using timeit:", end - start, "seconds")

Following is the output of the above code:

Time measured using timeit: 0.089123 seconds