Python – Compound Interest GUI Calculator using Tkinter

Prerequisites : Introduction to tkinter | Program to calculate compound interest

Python offers multiple options for developing a GUI (Graphical User Interface). Out of all the GUI methods, Tkinter is the most commonly used method. In this article, we will learn how to create a Compound Interest GUI Calculator application using Tkinter, with a step-by-step guide.

To create a Tkinter: 

• Importing the module – tkinter
• Create the main window (container)
• Add any number of widgets to the main window.
• Apply the event Trigger on the widgets.

Below is what the GUI will look like:

Let’s create a GUI based Compound Interest Calculator application.

Below is the implementation :

Python3

# import all classes / functions from the tkinter
from tkinter import *

# Function for clearing the
# contents of all entry boxes
def clear_all() :

    # whole content of entry boxes is deleted
    principle_field.delete(0, END)
    rate_field.delete(0, END)
    time_field.delete(0, END)
    compound_field.delete(0, END)

    # set focus on the principle_field entry box
    principle_field.focus_set()


# Function to find compound interest
def calculate_ci():

    # get a content from entry box
    principle = int(principle_field.get())

    rate = float(rate_field.get())

    time = int(time_field.get())

    # Calculates compound interest
    CI = principle * (pow((1 + rate / 100), time))

    # insert method inserting the
    # value in the text entry box.
    compound_field.insert(10, CI)



# Driver code
if __name__ == "__main__" :

    # Create a GUI window
    root = Tk()

    # Set the background colour of GUI window
    root.configure(background = 'light green')

    # Set the configuration of GUI window
    root.geometry("400x250")

    # set the name of tkinter GUI window
    root.title("Compound Interest Calculator")

    # Create a Principle Amount : label
    label1 = Label(root, text = "Principle Amount(Rs) : ",
                   fg = 'black', bg = 'red')

    # Create a Rate : label
    label2 = Label(root, text = "Rate(%) : ",
                   fg = 'black', bg = 'red')

    # Create a Time : label
    label3 = Label(root, text = "Time(years) : ",
                   fg = 'black', bg = 'red')

    # Create a Compound Interest : label
    label4 = Label(root, text = "Compound Interest : ",
                   fg = 'black', bg = 'red')

    # grid method is used for placing
    # the widgets at respective positions
    # in table like structure .

    # padx keyword argument used to set padding along x-axis .
    # pady keyword argument used to set padding along y-axis .
    label1.grid(row = 1, column = 0, padx = 10, pady = 10)
    label2.grid(row = 2, column = 0, padx = 10, pady = 10)
    label3.grid(row = 3, column = 0, padx = 10, pady = 10)
    label4.grid(row = 5, column = 0, padx = 10, pady = 10)

    # Create a entry box
    # for filling or typing the information.
    principle_field = Entry(root)
    rate_field = Entry(root)
    time_field = Entry(root)
    compound_field = Entry(root)

    # grid method is used for placing
    # the widgets at respective positions
    # in table like structure .

    # padx keyword argument used to set padding along x-axis .
    # pady keyword argument used to set padding along y-axis .
    principle_field.grid(row = 1, column = 1, padx = 10, pady = 10)
    rate_field.grid(row = 2, column = 1, padx = 10, pady = 10)
    time_field.grid(row = 3, column = 1, padx = 10, pady = 10)
    compound_field.grid(row = 5, column = 1, padx = 10, pady = 10)

    # Create a Submit Button and attached
    # to calculate_ci function
    button1 = Button(root, text = "Submit", bg = "red",
                     fg = "black", command = calculate_ci)

    # Create a Clear Button and attached
    # to clear_all function
    button2 = Button(root, text = "Clear", bg = "red",
                     fg = "black", command = clear_all)

    button1.grid(row = 4, column = 1, pady = 10)
    button2.grid(row = 6, column = 1, pady = 10)

    # Start the GUI
    root.mainloop()

Output :