Height and width as a float between 0.0 and 1.0, as a fraction of the height and width of the parent widget. code example

Example: place tkinter rip

from tkinter import *
root = Tk()
root.geometry("500x500")

btn_height = Button(root, text="50px high")
btn_height.place(height=50, x=200, y=200)

btn_width = Button(root, text="60px wide")
btn_width.place(width=60, x=300, y=300)

btn_relheight = Button(root, text="Relheight of 0.6")
btn_relheight.place(relheight=0.6)

btn_relwidth= Button(root, text="Relwidth of 0.2")
btn_relwidth.place(relwidth=0.2)

btn_relx=Button(root, text="Relx of 0.3")
btn_relx.place(relx=0.3)

btn_rely=Button(root, text="Rely of 0.7")
btn_rely.place(rely=0.7)

btn_x=Button(root, text="X = 400px")
btn_x.place(x=400)

btn_y=Button(root, text="Y = 321")
btn_y.place(y=321)

root.mainloop()