Welcome folks today in this blog post we will be building a basic simple arithmetic calculator in tkinter using python. All the full source code of the application is shown below.

Get Started

In order to get started you need to install the following library using the pip command as shown below

pip install tkinter

After installing make an app.py file and copy paste the following code

app.py

import tkinter as tk

calc = tk.Tk()
calc.title("CrappyCalc")

buttons = [
'7',  '8',  '9',  '*',  'C',
'4',  '5',  '6',  '/',  'Neg',
'1',  '2',  '3',  '-',  '$',
'0',  '.',  '=',  '+',  '@' ]

# set up GUI
row = 1
col = 0
for i in buttons:
    button_style = 'raised'
    action = lambda x = i: click_event(x)
    tk.Button(calc, text = i, width = 7, height = 7, relief = button_style, command = action) \
        .grid(row = row, column = col, sticky = 'nesw', )
    col += 1
    if col > 4:
        col = 0
        row += 1

display = tk.Entry(calc, width = 40, bg = "white")
display.grid(row = 0, column = 0, columnspan = 5)

def click_event(key):

    # = -> calculate results
    if key == '=':
        # safeguard against integer division
        if '/' in display.get() and '.' not in display.get():
            display.insert(tk.END, ".0")
            
        # attempt to evaluate results
        try:
            result = eval(display.get())
            display.insert(tk.END, " = " + str(result))
        except:
            display.insert(tk.END, "   Error, use only valid chars")
            
    # C -> clear display     
    elif key == 'C':
        display.delete(0, tk.END)
        
        
    # $ -> clear display     
    elif key == '$':
        display.delete(0, tk.END)
        display.insert(tk.END, "$$$$C.$R.$E.$A.$M.$$$$")
        

    # @ -> clear display     
    elif key == '@':
        display.delete(0, tk.END)
        display.insert(tk.END, "wwwwwwwwwwwwwwwwebsite")        

        
    # neg -> negate term
    elif key == 'neg':
        if '=' in display.get():
            display.delete(0, tk.END)
        try:
            if display.get()[0] == '-':
                display.delete(0)
            else:
                display.insert(0, '-')
        except IndexError:
            pass

    # clear display and start new input     
    else:
        if '=' in display.get():
            display.delete(0, tk.END)
        display.insert(tk.END, key)

# RUNTIME
calc.mainloop()

Now if you execute the above python script by using the below command as shown below

python app.py