Grade Calculator in Python

90 A, 80 B, ... else F. Check 0–100 first or a 107 becomes an A.

BeginnerConditional ProgramsExample 1 of 20

grade-calculator.py

1# Program to calculate grade from percentage
2
3percentage = float(input("Enter your percentage: "))
4
5if percentage < 0 or percentage > 100:
6    print("Invalid percentage. Please enter a value between 0 and 100.")
7else:
8    if percentage >= 90:
9        grade = 'A'
10    elif percentage >= 80:
11        grade = 'B'
12    elif percentage >= 70:
13        grade = 'C'
14    elif percentage >= 60:
15        grade = 'D'
16    else:
17        grade = 'F'
18
19    print(f"Your grade is: {grade}")

Output

Enter your percentage: 85
Your grade is: B

In this one

test the highest grade first
107 is invalid, not an A

What's going on

Walk the thresholds from the top. >= 90 then >= 80 and so on. Reverse that order and 95 matches >= 60 first and you hand out a D.

107% should not be an A. The 0–100 check is not decoration.

elif stops at the first hit. That's why 85 is B, not B and C.

After this program

If the idea is still fuzzy, read Day 8: Conditional Statements in the Python course. For a short check, try the Python quiz (300 questions). Stay with all 20 conditional programs, or see every topic on Python exercises.

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