app.py

from tkinter import *

# Creating a GUI Window
window = Tk()


def from_kg():
    # convert kg -> gram
    gram = float(e2_value.get()) * 1000

    # convert kg -> pound
    pound = float(e2_value.get()) * 2.20462

    # convert kg -> ounce
    ounce = float(e2_value.get()) * 35.274

    # Enters the converted weight to the text widget
    t1.delete('1.0', END)
    t1.insert(END, gram)

    t2.delete('1.0', END)
    t2.insert(END, pound)

    t3.delete('1.0', END)
    t3.insert(END, ounce)


# create the label widgets
e1 = Label(window, text='Enter the weight in KG(KiloGrams)')
e2_value = StringVar()
e2 = Entry(window, textvariable=e2_value)
e3 = Label(window, text='Gram')
e4 = Label(window, text='Pound')
e5 = Label(window, text='Ounce')

# create the text widgets
t1 = Text(window, height=1, width=20)
t2 = Text(window, height=1, width=21)
t3 = Text(window, height=1, width=22)

# create the button widget
b1 = Button(window, text='Convert', command=from_kg)

# grid method is used for placing the widgets at respective positions in table like structure.
e1.grid(row=0, column=0)
e2.grid(row=0, column=1)
e3.grid(row=1, column=0)
e4.grid(row=1, column=1)
e5.grid(row=1, column=2)
t1.grid(row=2, column=0)
t2.grid(row=2, column=1)
t3.grid(row=2, column=2)
b1.grid(row=0, column=2)

# start the GUI
window.mainloop()