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Simple GUI Calculator using Python Tkinter


The following examples shows, how to create simple GUI calculator Application using Python Tkinter.

First, we have to install tkinter

pip install tk

Calculator App

from tkinter import *  
from tkinter import messagebox 
from functools import partial

root=Tk()
root.title("Calc")
root.geometry("220x260")

txtBox=StringVar()
evalBox=StringVar()
txtBox.set("")  
evalBox.set("")  
def set_text(ch):
    txt=txtBox.get()  
    txtBox.set("{}{}".format(txt,ch))
    
def operator(opr):
    evl=evalBox.get()
    txt=txtBox.get()     
    if txt=="":
        return
    evalBox.set("{}{}{}".format(evl,txt,opr))
    txtBox.set("")  
    
def calculate():
    evl=evalBox.get()  
    txt=txtBox.get() 
    
    evalBox.set("{}{}".format(evl,txt))

    txtBox.set("")
    evl=evalBox.get() 
    oprs=['+','-','*','/']
    c=evl[-1:]
    if c in oprs:
       evl=evl[:-1]
    txtBox.set(str(eval(evl)))
    
def clr_text():
    txtBox.set("") 
    evalBox.set("") 
    
Entry(root,textvariable = evalBox,font = ('Arial',8,'normal'),width=30,justify='right',state='readonly').place(x=10,y=1)
Entry(root,textvariable = txtBox,font = ('Arial',18,'normal'),width=14,justify='right',state='readonly').place(x=10,y=20)

Button(root,text=" 7 ",font=('Arial', 13),command=partial(set_text,"7"),padx=5,pady=5).place(x=10,y=60)
Button(root,text=" 8 ",font=('Arial', 13),command=partial(set_text,"8"),padx=5,pady=5).place(x=60,y=60)
Button(root,text=" 9 ",font=('Arial', 13),command=partial(set_text,"9"),padx=5,pady=5).place(x=110,y=60)
Button(root,text=" / ",font=('Arial', 13),command=partial(operator,"/"),padx=5,pady=5).place(x=160,y=60)

Button(root,text=" 4 ",font=('Arial', 13),command=partial(set_text,"4"),padx=5,pady=5).place(x=10,y=110)
Button(root,text=" 5 ",font=('Arial', 13),command=partial(set_text,"5"),padx=5,pady=5).place(x=60,y=110)
Button(root,text=" 6 ",font=('Arial', 13),command=partial(set_text,"6"),padx=5,pady=5).place(x=110,y=110)
Button(root,text=" * ",font=('Arial', 13),command=partial(operator,"*"),padx=5,pady=5).place(x=160,y=110)

Button(root,text=" 1 ",font=('Arial', 13),command=partial(set_text,"1"),padx=5,pady=5).place(x=10,y=160)
Button(root,text=" 2 ",font=('Arial', 13),command=partial(set_text,"2"),padx=5,pady=5).place(x=60,y=160)
Button(root,text=" 3 ",font=('Arial', 13),command=partial(set_text,"3"),padx=5,pady=5).place(x=110,y=160)
Button(root,text=" - ",font=('Arial', 13),command=partial(operator,"-"),padx=5,pady=5).place(x=160,y=160)

Button(root,text=" C ",font=('Arial', 12),command=clr_text,padx=5,pady=5).place(x=10,y=210)
Button(root,text=" 0 ",font=('Arial', 13),command=partial(set_text,"0"),padx=5,pady=5).place(x=60,y=210)
Button(root,text=" = ",font=('Arial', 13),command=calculate,padx=5,pady=5).place(x=110,y=210)
Button(root,text=" + ",font=('Arial', 12),command=partial(operator,"+"),padx=5,pady=5).place(x=160,y=210)

root.mainloop()