Python For Loops Explained (GCSE Examples)

June 19, 2026

A for loop repeats a block of code a set number of times. Loops are one of the most heavily tested ideas in GCSE programming, so it is worth getting comfortable with them. This guide explains them with examples you can run right away.

The basic for loop

This prints the numbers 0 to 4:

for i in range(5):
  print(i)

range(5) produces the numbers 0, 1, 2, 3, 4 — it starts at 0 and stops before 5. The variable i takes each value in turn.

Counting from a different number

range(start, stop) lets you choose where to begin:

for n in range(1, 6):
  print(n) # prints 1 to 5

Counting in steps

for n in range(0, 21, 5):
  print(n) # 0, 5, 10, 15, 20

Looping over a list

You can loop directly over the items in a list:

colours = ["red", "green", "blue"]
for c in colours:
  print(c)

A worked example: total of a list

scores = [12, 8, 15, 6]
total = 0
for s in scores:
  total = total + s
print(total) # 41

Common mistakes

• Forgetting that range(n) stops at n-1.
• Indenting the loop body incorrectly — Python uses indentation to know what is inside the loop.
• Using a for loop when you do not know how many times to repeat (use a while loop instead).

The best way to learn loops is to run them. Open the free online Python IDE, paste in these examples, and change the numbers to see what happens.