Overview
A mortgage calculator is a tool that helps users calculate their monthly mortgage payments based on the loan amount, interest rate, and loan term. In this tutorial, we will be creating a mortgage calculator using Tkinter, a Python library for creating graphical user interfaces.
Setting up the Tkinter
environment: Before we can start creating our calculator, we need to set up the Tkinter environment. This can be done by importing the Tkinter library and creating a new Tkinter object, which will serve as the main window for our calculator.
import tkinter as tk
root = tk.Tk()
Creating the GUI layout
Once we have our Tkinter environment set up, we can start creating the layout for our calculator. This can be done by adding various Tkinter widgets, such as labels, entry fields, and buttons. In this example, we will have labels for the loan amount, interest rate, and loan term, as well as entry fields for the user to input this information. We will also have a button to calculate the monthly payment.
# Create labels
loan_amount_label = tk.Label(root, text="Loan Amount:")
interest_rate_label = tk.Label(root, text="Interest Rate:")
loan_term_label = tk.Label(root, text="Loan Term (years):")
# Create entry fields
loan_amount_entry = tk.Entry(root)
interest_rate_entry = tk.Entry(root)
loan_term_entry = tk.Entry(root)
# Create calculate button
calculate_button = tk.Button(root, text="Calculate")
# Add widgets to the main window
loan_amount_label.pack()
loan_amount_entry.pack()
interest_rate_label.pack()
interest_rate_entry.pack()
loan_term_label.pack()
loan_term_entry.pack()
calculate_button.pack()
Adding functionality to the calculator
Now that we have our layout set up, we can add functionality to the calculator. This can be done by creating a function that will be called when the calculate button is pressed. This function will take the values from the entry fields, perform the necessary calculations, and display the monthly payment.
# Function to calculate monthly payment
def calculate_payment():
loan_amount = float(loan_amount_entry.get())
interest_rate = float(interest_rate_entry.get())
loan_term = float(loan_term_entry.get())
# Calculation for monthly payment
monthly_payment = loan_amount * (interest_rate / (1 - (1 + interest_rate) ** (-loan_term * 12)))
# Display the monthly payment
tk.Label(root, text="Monthly Payment: ${:.2f}".format(monthly_payment)).pack()
# Set command for calculate button
calculate_button.config(command=calculate_payment)
Full Code Above
import tkinter as tk
def calculate_payment():
loan_amount = float(loan_amount_entry.get())
interest_rate = float(interest_rate_entry.get()) / 100
loan_term = float(loan_term_entry.get())
# Calculation for monthly payment
monthly_payment = loan_amount * (interest_rate / (1 - (1 + interest_rate) ** (-loan_term * 12)))
# Display the monthly payment
tk.Label(root, text="Monthly Payment: ${:.2f}".format(monthly_payment)).pack()
root = tk.Tk()
# Create labels
loan_amount_label = tk.Label(root, text="Loan Amount:")
interest_rate_label = tk.Label(root, text="Interest Rate(%):")
loan_term_label = tk.Label(root, text="Loan Term (years):")
# Create entry fields
loan_amount_entry = tk.Entry(root)
interest_rate_entry = tk.Entry(root)
loan_term_entry = tk.Entry(root)
# Create calculate button
calculate_button = tk.Button(root, text="Calculate", command=calculate_payment)
# Add widgets to the main window
loan_amount_label.pack()
loan_amount_entry.pack()
interest_rate_label.pack()
interest_rate_entry.pack()
loan_term_label.pack()
loan_term_entry.pack()
calculate_button.pack()
root.mainloop()
Output Application
Running the calculator
To run the calculator, we simply need to call the mainloop() function on the Tkinter object we created earlier. This will start the event loop and display the calculator on the screen.
root.mainloop()
With this, our mortgage calculator is now complete and ready to use! Users can input the loan amount, interest rate, and loan term and press the calculate button to see their monthly payment.
External link source :
- https://docs.python.org/3/library/tk.html
- https://www.tutorialspoint.com/python/python_gui_programming.htm
- https://www.w3schools.com/python/python_gui_tkinter.asp
- https://realpython.com/python-gui-tkinter/
