>>> from matplotlib import rcParams
>>> import os.path

>>> afm_filename = os.path.join(rcParams['datapath'], 'fonts', 'afm', 'ptmr8a.afm')
>>>
>>> from matplotlib.afm import AFM
>>> afm = AFM(open(afm_filename))
>>> afm.string_width_height('What the heck?')
(6220.0, 694)

# Python 3 names -- see Note below
import tkinter
from tkinter import font as tkFont

tkinter.Frame().destroy()  # Enough to initialize resources
arial36b = tkFont.Font(family='Arial', size=36, weight='bold')
width = arial36b.measure("How wide is this?")
print(width)  # Prints: 404

import Tkinter
import tkFont

import ctypes

def GetTextDimensions(text, points, font):
    class SIZE(ctypes.Structure):
        _fields_ = [("cx", ctypes.c_long), ("cy", ctypes.c_long)]

    hdc = ctypes.windll.user32.GetDC(0)
    hfont = ctypes.windll.gdi32.CreateFontA(-points, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, font)
    hfont_old = ctypes.windll.gdi32.SelectObject(hdc, hfont)
    size = SIZE(0, 0)
    ctypes.windll.gdi32.GetTextExtentPoint32A(hdc, text, len(text), ctypes.byref(size))
    ctypes.windll.gdi32.SelectObject(hdc, hfont_old)
    ctypes.windll.gdi32.DeleteObject(hfont)
    return (size.cx, size.cy)

for text, font in [
    ('....', 'Arial'),
    ('WWWW', 'Arial'),
    ('WWWW', 'Arial Narrow'),
    ('....', 'Courier New'),
    ('WWWW', 'Courier New'),
    ("Test", "Unknown font"),
    ('Test', 'Calibri')]: