Last Updated : 15 Jul, 2025
Python offers multiple options for developing a GUI (Graphical User Interface). Out of all the Python GUI Libraries, Tkinter is the most commonly used method. In this article, we will learn how to create a Compound Interest GUI Calculator application using Tkinter.
Let’s create a GUI-based Compound Interest Calculator application.
Below is what the GUI will look like:
Steps to Create Compound Interest GUI Calculator using Tkinter Importing thetkinter Library:
from tkinter import *
This imports all classes and functions from the tkinter library, which is used to create the GUI.
Function to Clear All Entry FieldsThis function clears the content of all entry fields and sets the focus back to the principal_field.
Python
def clear_all():
principal_field.delete(0, END)
rate_field.delete(0, END)
time_field.delete(0, END)
compound_field.delete(0, END)
principal_field.focus_set()
Function to Calculate Compound Interest:
This function retrieves values from the entry fields, calculates the compound interest, and inserts the result into the compound_field.
Python
def calculate_ci():
principal = int(principal_field.get())
rate = float(rate_field.get())
time = int(time_field.get())
CI = principal * (pow((1 + rate / 100), time))
compound_field.insert(10, CI)
Main Program:
This part initializes the main window of the GUI, sets the background color, window size, and title.
Python
if __name__ == "__main__":
root = Tk()
root.configure(background = 'light green')
root.geometry("400x250")
root.title("Compound Interest Calculator")
Creating and Positioning Labels:
These lines create labels for the GUI and position them using the grid method.
Python
label1 = Label(root, text = "Principal Amount(Rs) : ", fg = 'black', bg = 'red')
label2 = Label(root, text = "Rate(%) : ", fg = 'black', bg = 'red')
label3 = Label(root, text = "Time(years) : ", fg = 'black', bg = 'red')
label4 = Label(root, text = "Amount : ", fg = 'black', bg = 'red')
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)
Creating and Positioning Entry Fields:
These lines create entry fields for user input and position them using the grid method.
Python
principal_field = Entry(root)
rate_field = Entry(root)
time_field = Entry(root)
compound_field = Entry(root)
principal_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)
Creating and Positioning Buttons:
These lines create buttons for submitting the form and clearing the fields, and position them using the grid method.
Python
button1 = Button(root, text = "Submit", bg = "red",
fg = "black", command = calculate_ci)
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)
Starting the GUI Event Loop:
root.mainloop()Complete Code Python
# 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
principal_field.delete(0, END)
rate_field.delete(0, END)
time_field.delete(0, END)
compound_field.delete(0, END)
# set focus on the principal_field entry box
principal_field.focus_set()
# Function to find compound interest
def calculate_ci():
# get a content from entry box
principal = int(principal_field.get())
rate = float(rate_field.get())
time = int(time_field.get())
# Calculates compound interest
CI = principal * (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 Principal Amount : label
label1 = Label(root, text = "Principal 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 = "Amount : ",
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.
principal_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 .
principal_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
Create a Compound Interest GUI Calculator using Tkinter
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4