CustomTkinter Tutorial Build Beautiful Desktop Apps with Python Easily

Building desktop applications with Python has always been popular among developers because of its simplicity and flexibility. However, traditional GUI libraries like Tkinter often feel outdated in design and limited in customization. This is where CustomTkinter comes in as a modern solution.

CustomTkinter is an enhanced version of Tkinter that allows developers to create modern, clean, and visually appealing desktop applications without needing advanced UI/UX design skills. It keeps the simplicity of Tkinter while adding a fresh, modern design system similar to today’s mobile and web applications.

What is CustomTkinter

CustomTkinter is a Python library built on top of Tkinter. It provides modern UI components such as:

• Modern buttons
• Stylish entry fields
• Advanced frames and layouts
• Dark and light themes
• Responsive design elements

Unlike standard Tkinter widgets, CustomTkinter components are designed with modern user interface principles, making your applications look professional and visually attractive.

It is widely used for:

• Desktop software
• Admin dashboards
• Data entry tools

Why Use CustomTkinter?

Many developers prefer CustomTkinter because it solves common problems found in traditional Tkinter.

1. Modern Look and Feel

Tkinter applications often look outdated. CustomTkinter gives your app a clean, modern interface similar to Flutter or React-based UI designs.

2. Easy to Learn

If you already know basic Tkinter, learning CustomTkinter is extremely easy because it uses similar syntax.

3. Dark and Light Mode Support

Modern users expect theme switching. CustomTkinter provides built-in support for:

• Dark mode
• Light mode
• System-based themes

4. Highly Customizable

You can adjust:

• Colors
• Shapes
• Sizes
• Hover effects
• Fonts

5. Lightweight and Fast

Even though it looks modern, it remains lightweight and runs smoothly on most systems.

Installing CustomTkinter

Before starting development, you need to install the library.

Step 1: Install using pip

Open your terminal or command prompt and run:

pip install customtkinter

Step 2: Verify Installation

You can test it with:

import customtkinter
print("CustomTkinter installed successfully!")

If no error appears, you are ready to build applications.

Creating Your First CustomTkinter App

Let’s start by creating a simple window.

Basic Window Example

import customtkinter as ctk

# Set appearance mode
ctk.set_appearance_mode("dark")

# Set default color theme
ctk.set_default_color_theme("blue")

# Create main window
app = ctk.CTk()
app.title("My First CustomTkinter App")
app.geometry("500x400")

# Run application
app.mainloop()

Explanation

• CTk() creates the main window
• set_appearance_mode() sets dark or light mode
• geometry() defines window size
• mainloop() keeps the app running

This is your first modern Python desktop app.

Adding Labels in CustomTkinter

Labels are used to display text.

label = ctk.CTkLabel(app, text="Welcome to CustomTkinter!")
label.pack(pady=20)

Key Points

• CTkLabel is used instead of Tkinter Label
• pack() positions the widget
• pady adds vertical spacing

You can also customize font and color:

label = ctk.CTkLabel(
    app,
    text="Modern Python GUI",
    font=("Arial", 20)
)
label.pack(pady=20)

Creating Buttons in CustomTkinter

Buttons are essential for interaction.

def click_button():
    print("Button clicked!")

button = ctk.CTkButton(app, text="Click Me", command=click_button)
button.pack(pady=20)

Explanation

• command defines what happens when the button is clicked
• Functions handle user interaction

You can also customize buttons:

button = ctk.CTkButton(
    app,
    text="Submit",
    fg_color="green",
    hover_color="darkgreen"
)
button.pack(pady=20)

Entry Fields (User Input)

Entry fields allow users to input text.

entry = ctk.CTkEntry(app, placeholder_text="Enter your name")
entry.pack(pady=20)

Getting Input Value

def show_name():
    print(entry.get())

button = ctk.CTkButton(app, text="Show Name", command=show_name)
button.pack(pady=10)

Frames for Better Layout

Frames help organize widgets.

frame = ctk.CTkFrame(app)
frame.pack(pady=20, padx=20, fill="both", expand=True)

label = ctk.CTkLabel(frame, text="Inside Frame")
label.pack(pady=10)

Why Frames Matter

They help:

• Structure your UI
• Group related elements
• Improve design clarity

Working with Themes

CustomTkinter allows easy theme switching.

Light Mode

ctk.set_appearance_mode("light")

Dark Mode

ctk.set_appearance_mode("dark")

System Mode

ctk.set_appearance_mode("system")

System mode automatically matches your operating system settings.

Building a Simple Login Form

Let’s combine everything into a small project.

import customtkinter as ctk

ctk.set_appearance_mode("dark")
ctk.set_default_color_theme("blue")

app = ctk.CTk()
app.geometry("400x300")
app.title("Login Form")

# Username
username_entry = ctk.CTkEntry(app, placeholder_text="Username")
username_entry.pack(pady=10)

# Password
password_entry = ctk.CTkEntry(app, placeholder_text="Password", show="*")
password_entry.pack(pady=10)

# Login function
def login():
    username = username_entry.get()
    password = password_entry.get()
    print("Username:", username)
    print("Password:", password)

# Button
login_button = ctk.CTkButton(app, text="Login", command=login)
login_button.pack(pady=20)

app.mainloop()

This simple app demonstrates:

• Input fields
• Button handling
• Basic layout
• User interaction

CustomTkinter vs Tkinter

Feature	Tkinter	CustomTkinter
Design	Old-style	Modern UI
Themes	Limited	Dark/Light/System
Customization	Low	High
Ease of use	Easy	Easy
Appearance	Basic	Professional

CustomTkinter clearly wins when it comes to modern UI design.

Best Practices for CustomTkinter Development

To build professional applications, follow these tips:

1. Use Consistent Themes

Stick to one color theme throughout your application.

2. Organize with Frames

Avoid placing all widgets directly on the main window.

3. Keep UI Simple

Modern design prefers minimalism.

4. Use Proper Spacing

Padding improves readability and user experience.

5. Use Functions for Logic

Never mix UI code with business logic.

Common Use Cases

CustomTkinter is used in many real-world applications such as:

• School management systems
• Inventory management tools
• Data visualization dashboards
• Personal productivity apps
• Admin panels for small businesses

Its simplicity makes it ideal for both beginners and professionals.

Advantages of CustomTkinter

CustomTkinter offers several benefits:

• Easy to learn for beginners
• Clean and modern UI design
• Fast development cycle
• Cross-platform support
• Active community support

These advantages make it a strong choice for Python GUI development.

Limitations

Although powerful, it has some limitations:

• Not suitable for very large enterprise applications
• Limited compared to frameworks like Qt
• Requires manual design for complex layouts

Still, for most small and medium projects, it is more than enough.

Conclusion

CustomTkinter is a powerful and modern solution for building desktop applications using Python. It enhances the traditional Tkinter library by adding stylish UI components, theme support, and better customization options.