while Loops

Repeat while something is true

A while loop keeps going as long as its condition is True. Use it when you don't know in advance how many times to repeat.

count = 1
while count <= 5:
    print("Count is", count)
    count += 1
print("Done!")

Output

Count is 1
Count is 2
Count is 3
Count is 4
Count is 5
Done!

Each time round, Python checks count <= 5. When count becomes 6 the condition is False and the loop stops.

Think of it like this: “While the kettle isn't boiling, keep waiting.” You don't know how many seconds it will take – you just keep checking.

A real example: saving money

savings = 0
weeks = 0
while savings < 1000:
    savings += 150
    weeks += 1
print(f"It takes {weeks} weeks to save {savings} rupees")

Output

It takes 7 weeks to save 1050 rupees

Asking until the answer is right

password = ""
while password != "python":
    password = input("Password: ")
print("Welcome!")

Output (when you type hello, Python, then python)

Password: hello
Password: Python
Password: python
Welcome!

Common mistake: An infinite loop never ends because the condition never becomes False – usually because you forgot to change the variable (like count += 1). If your program seems stuck, check this first.

Tip: Use for when you know how many times to repeat. Use while when you repeat “until something happens”.