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CurriculumPython for Loops and range() for KidsWhat range() actually counts

Why range(5) Doesn't Count to 5 in Python

range(n) gives n numbers starting at 0 — and never reaches n itself.

Lesson 2 of 5PROAges 10+
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What range() actually counts

Here's the single trickiest thing about range(). Watch closely.

range(4) does NOT count 1, 2, 3, 4. It counts 0, 1, 2, 3 — starting at zero.

for i in range(4):
    print(i)

Output

0
1
2
3

That's still four numbers — range(4) always gives exactly 4 values. It just starts one earlier than most people expect.

for i in range(4):
    print(i)

And it STOPS before reaching 4. The number inside range() is never itself one of the results.

for i in range(4):
    print(i)

Output

0
1
2
3

Want to count from 1 instead? Don't fight range() — just add 1 to what you print.

for i in range(3):
    print(i + 1)

Output

1
2
3

Check your understanding

What does range(5) actually produce?

  • 0, 1, 2, 3, 4
  • 1, 2, 3, 4, 5
  • 0, 1, 2, 3, 4, 5

Why: range(5) gives exactly five numbers, starting at 0: 0, 1, 2, 3, 4. The number you put in is how MANY values you get, not the last value you see — that's the part that trips almost everyone up at first.

You want the numbers 1 through 5 (five numbers, starting at 1). Which is right?

  • for i in range(5): print(i + 1)
  • for i in range(6): print(i)
  • for i in range(1, 5): print(i)

Why: range(5) reliably gives 5 values (0-4), and adding 1 to each shifts them to 1-5 without having to recompute the range size. Both of the other options are off by exactly one, in different directions.

What you'll practice

There are 4 treasure chests, numbered starting from 0. Print each chest's number, one per line.

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More from this topic

What range() actually counts is one lesson inside Python for Loops and range() for Kids — see the full lesson order and what the whole topic covers.

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