How to Change The Tkinter Button Size

1. Specify height and width Options to Set Button Size
2. Set width and height in Pixels of Tkinter Button
3. Change Tkinter Button Size After Initialization

height and width options of Tkinter Button widget specify the size of the created button during the initialization. After initialization, we could still use the configure method to configure the height and width option to change the size of the Tkinter Button widget programmatically.

Specify height and width Options to Set Button Size

tk.Button(self, 
          text = "", 
          height = 20, 
          width = 20)

The height and width are set to be 20 in the unit of text units. The horizontal text unit is equal to the width of the character 0, and the vertical text unit is equal to the height of 0, both in the default system font.

Complete Working Codes

import tkinter as tk
import tkinter.font as tkFont
    
app = tk.Tk()
app.geometry("400x200")

    
buttonExample1 = tk.Button(app,
                           text="Button 1",
                           width=10,
                           height=10)
buttonExample2 = tk.Button(app,
                           text="Button 2",
                           width=10,
                           height=10)

buttonExample1.pack(side=tk.LEFT)
buttonExample2.pack(side=tk.RIGHT)

app.mainloop()

As you could see, the height and width of the button are not the same in the pixels although its width and width are set to be both 10.

Set width and height in Pixels of Tkinter Button

If we need to specify the width and/or height of Tkinter Button widget in the unit of pixels, we could add a virtual invisible 1x1 pixel image to the Button. Then the width and height will be measured in the unit of pixel.

tk.Button(app,
          text="Button 1",
          image=pixelVirtual,
          width=100,
          height=100,
          compound="c")

We also need to set the compound option to be c or equally tk.CENTER if the invisible image and text should be centered in the button. If compound is not configured, the text will not show in the button.

import tkinter as tk
import tkinter.font as tkFont
    
app = tk.Tk()
app.geometry("300x100")
fontStyle = tkFont.Font(family="Lucida Grande", size=20)

labelExample = tk.Label(app, text="20", font=fontStyle)

pixelVirtual = tk.PhotoImage(width=1, height=1)
    
buttonExample1 = tk.Button(app,
                           text="Increase",
                           image=pixelVirtual,
                           width=100,
                           height=100,
                           compound="c")
buttonExample2 = tk.Button(app,
                           text="Decrease",
                           image=pixelVirtual,
                           width=100,
                           height=100,
                           compound="c")

buttonExample1.pack(side=tk.LEFT)
buttonExample2.pack(side=tk.RIGHT)
app.mainloop()

Change Tkinter Button Size After Initialization

After the Button widget has been created, the configure method could set the width and/or height options to change the Button size.

buttonExample1.configure(height = 100,
                             width = 100)

It sets the height and width of buttonExample1 to be 100.

Complete Working Examples to Change Button Size After Initialization

import tkinter as tk
import tkinter.font as tkFont
    
app = tk.Tk()
app.geometry("600x500")

def decreaseSize():
    buttonExample1.configure(height = 100,
                             width = 100)

def increaseSize():
    buttonExample2.configure(height = 400,
                             width = 400)

pixelVirtual = tk.PhotoImage(width=1, height=1)
    
buttonExample1 = tk.Button(app,
                           text="Decrease Size",
                           image=pixelVirtual,
                           width=200,
                           height=200,
                           compound="c",
                           command = decreaseSize)
buttonExample2 = tk.Button(app,
                           text="Increase Size",
                           image=pixelVirtual,
                           width=200,
                           height=200,
                           compound=tk.CENTER,
                           command = increaseSize)

buttonExample1.pack(side=tk.LEFT)
buttonExample2.pack(side=tk.RIGHT)
app.mainloop()

Related Article - Tkinter Button