diff --git a/README.md b/README.md
index bfe70ef..23ac908 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,15 @@
 # Timeline
 A tool for creating SVG timelines from JSON.  
 
+### Prerequisites
+
+Install tkinter and required packages using:
+
+```shell
+$ sudo apt install  python3-tk
+$ sudo apt install -r requirements.txt
+```
+
 ### Example
 
 You will be able to create timelines that look like this:
diff --git a/make_timeline.py b/make_timeline.py
index 7f8beb5..7881c6f 100755
--- a/make_timeline.py
+++ b/make_timeline.py
@@ -7,8 +7,8 @@
 import json
 import os.path
 import sys
-import tkFont
-import Tkinter
+import tkinter
+import tkinter.font as TkFont
 
 class Colors:
 	black = '#000000'
@@ -44,7 +44,7 @@ def __init__(self, filename):
 		self.tick_format = self.data.get('tick_format', None)
 		self.markers = {}
 		# initialize Tk so that font metrics will work
-		self.tk_root = Tkinter.Tk()
+		self.tk_root = tkinter.Tk()
 		self.fonts = {}
 		# max_label_height stores the max height of all axis labels
 		# and is used in the final height computation in build(self)
@@ -232,24 +232,24 @@ def get_text_metrics(self, family, size, text):
 		if key in self.fonts:
 			font = self.fonts[key]
 		else:
-			font = tkFont.Font(family=family, size=size)
+			font = TkFont.Font(family=family, size=size)
 			self.fonts[key] = font
 		assert font is not None
 		w, h = (font.measure(text), font.metrics("linespace"))
 		return w, h
 
 def usage():
-	print 'Usage: ./make_timeline.py in.json > out.svg'
+	print('Usage: ./make_timeline.py in.json > out.svg')
 	sys.exit(-1)
 
 if __name__ == '__main__':
 	if len(sys.argv) < 2:
-		print 'missing input filename'
+		print('missing input filename')
 		usage()
 	filename = sys.argv[1]
 	if not os.path.isfile(filename):
-		print 'file %s not found' % filename
+		print('file %s not found' % filename)
 		sys.exit(-1)
 	timeline = Timeline(filename)
 	timeline.build()
-	print timeline.to_string().encode('utf-8')
+	print(timeline.to_string().encode('utf-8'))
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..71e376f
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,4 @@
+# run `sudo apt install  python3-tk` if required
+parsedatetime
+svgwrite
+tk-tools
\ No newline at end of file