Introduction

Grading systems help evaluate student performance based on marks. In this post, we'll build a simple grade calculator using Tkinter in Python. The user enters marks, clicks a button, and the program displays the grade.

Code: Grade Calculator using Tkinter 

from tkinter import *

def calculate_grade():
    marks = float(e1.get())

    if marks >= 90:
        grade = "A"
    elif marks >= 80:
        grade = "B"
    elif marks >= 70:
        grade = "C"
    elif marks >= 60:
        grade = "D"
    else:
        grade = "F"

    l3.config(text=f"Grade: {grade}")

b = Tk()
b.title("Grade Calculator")
b.geometry("300x200")

l1 = Label(b, text="Enter Marks:")
l1.pack()

e1 = Entry(b)
e1.pack()

b1 = Button(b, text="Check Grade", command=calculate_grade)
b1.pack()

l3 = Label(b, text="Grade: ")
l3.pack()

b.mainloop()

Explanation of Code

Step 1: Import Tkinter

We import Tkinter using from tkinter import *, which allows us to create GUI components.

Step 2: Function to Calculate Grade

  • calculate_grade() fetches the value from the entry field (e1.get()).
  • It converts the value to float (since marks may have decimals).
  • The if-elif conditions determine the grade based on marks:
  1. 90+ → A
  2. 80-89 → B
  3. 70-79 → C
  4. 60-69 → D
  5. Below 60 → F

The grade is displayed using l3.config(text=f"Grade: {grade}").

Step 3: Creating the Tkinter Window

  • b = Tk() initializes the main application window.
  • b.title("Grade Calculator") sets the window title.
  • b.geometry("300x200") sets the window size.

Step 4: Adding Widgets

  • Label (l1) – Displays "Enter Marks:".
  • Entry (e1) – User types marks here.
  • Button (b1) – Calls calculate_grade() when clicked.
  • Result Label (l3) – Displays the grade after clicking the button.

Step 5: Running the Application

b.mainloop() keeps the GUI open and responsive.

Conclusion

This simple Tkinter project helps visualize how conditional statements work in Python. You can expand it by adding:
✅ GPA Calculator (average of multiple subjects).
✅ Color-coded Grades (Green for A, Red for F).
✅ Additional Features (Remarks like "Excellent", "Needs Improvement").

Try modifying it and share your version!