How do I center a frame within a frame in Tkinter?

pack it to fill in all directions. Add padding as needed.

Or, use place which lets you use relative or absolute positioning. You can use a relative x/y of .5/.5 and an anchor of "c" (center).

import Tkinter as tkroot=tk.Tk()f1 = tk.Frame(width=200, height=200, background="red")f2 = tk.Frame(width=100, height=100, background="blue")f1.pack(fill="both", expand=True, padx=20, pady=20)f2.place(in_=f1, anchor="c", relx=.5, rely=.5)root.mainloop()

If you want to center a widget (like a frame) inside a frame, the easiest way to do it is via .grid(). If you use .pack(), you end up stuck along one of the edges, since pack() has the side keyword.

If you use .place(), then you're stuck forcing the size of the outer frame (which normally you don't have to do, but you've already done it, so it's not an issue), because placed widgets aren't detected when the frame autosizes like with packed or gridded widgets. I'm not sure why, but that's the way it is.

So, in general, the best way to center a widget inside a frame is to grid the widget into the frame. (The sticky option defaults to CENTER.) And then, if you want to be able to resize the outer frame and have the widget stay centered, you need to allow the outer frame's cell to expand/grow. You would do this via the .grid_rowconfigure() etc commands. So, an example might be:

        widget = Widget(frame, ...)        widget.grid(row=0, column=0, sticky="")        frame.grid_rowconfigure(0, weight=1)        frame.grid_columnconfigure(0, weight=1)