Online Python Compiler
Free · No login · Runs in your browserWrite and run real Python 3 programs — with input() and NumPy — right here. Made for NIELIT O Level (M3 & PR-3), CCC and school students.
Write your code
Input
Output
How to Use This Online Python Compiler
- Type your program in the dark editor, or pick one from Examples.
- If your program uses
input(), type the answers in Program Input, one per line. - Press Run (or Ctrl + Enter). The first run takes a few seconds while Python loads; after that it is instant.
- Read the result in Output. Errors appear there too, with the line number that caused them.
- Use Share code to send your program to a friend or teacher on WhatsApp — the link opens with your code already in the editor.
What You Can Practice Here
Everything in the NIELIT O Level M3-R5.1 (Programming and Problem Solving through Python) syllabus runs here: variables and operators, if/elif/else, for and while loops, strings and slicing, lists, tuples, sets, dictionaries, functions and recursion, exception handling with try/except, classes, and NumPy arrays.
The examples above are the kind of programs asked in the PR-3 practical exam — prime numbers, factorial, Fibonacci series, patterns, palindromes, list statistics, character counting and NumPy matrix operations. Change the numbers, break the program on purpose, and read the error: that is the fastest way to learn.
Why Your Code Is Safe and Private
This compiler does not send your code anywhere. Python itself is downloaded into your browser and runs there, inside a separate worker, so a mistake such as an endless loop cannot freeze the page — it is simply stopped after 15 seconds. Your last program is remembered on this device, so you can close the tab and continue later.
Frequently Asked Questions
Is this online Python compiler free?
Yes, completely free, with no login and no limit on how many programs you run. The Python interpreter runs inside your own browser, so your code is never sent to a server.
Which Python version does it run?
It runs real CPython 3 compiled to WebAssembly (Pyodide), not a simplified imitation. Standard Python syntax, functions, classes, lists, dictionaries, strings, exceptions and most of the standard library work exactly as they do on a computer.
How do I use input() in this compiler?
Type the values your program asks for in the Program Input box before pressing Run, one value per line. The first input() reads the first line, the second input() reads the second line, and so on.
Can I use NumPy?
Yes. Write import numpy as np and press Run. The first run downloads NumPy, which takes a few seconds; after that it is instant. NumPy is part of the NIELIT O Level M3-R5.1 (Python) syllabus.
What does not work?
Programs that open a window (turtle, tkinter), read or write files on your computer, or connect to the internet will not work, because everything runs safely inside the browser. A program that runs for more than 15 seconds is stopped, which protects you from endless loops.
Is this useful for the O Level PR-3 practical exam?
Yes. It is the same Python engine used in our free O Level PR-3 practical mock test, so you can write and check every practical program here and then attempt a timed paper when you are ready.
Does it work on a mobile phone?
Yes. It works in Chrome on Android and Safari on iPhone. The first run takes a little longer on mobile data because Python is downloaded once.