diff --git a/escpos/cli.py b/escpos/cli.py
index 1a52dcb..4b52381 100755
--- a/escpos/cli.py
+++ b/escpos/cli.py
@@ -90,7 +90,7 @@ def echo(args):  # pylint: disable=unused-argument
                 epson.barcode(data, bctype, 48, 2, '', '')
                 epson.set(align='left')
             else:
-                epson.text('%s\n' % line)
+                epson.text('{0}\n'.format(line))
     except KeyboardInterrupt:
         epson.cut()
 
@@ -143,7 +143,7 @@ def _test_barcodes():
     ):
         # TODO: Fix the library to restore old alignment somehow
         epson.set(align='center')
-        epson.text('\n%s\n' % name)
+        epson.text('\n{0}\n'.format(name))
         epson.barcode(data, name, 64, 2, '', '')
 
 
diff --git a/escpos/escpos.py b/escpos/escpos.py
index 3a8c39a..dc8912e 100644
--- a/escpos/escpos.py
+++ b/escpos/escpos.py
@@ -348,12 +348,12 @@ class Escpos(object):
         if 1 <= height <= 255:
             self._raw(BARCODE_HEIGHT + chr(height))
         else:
-            raise BarcodeSizeError("height = %s" % height)
+            raise BarcodeSizeError("height = {height}".format(height=height))
         # Width
         if 2 <= width <= 6:
             self._raw(BARCODE_WIDTH + chr(width))
         else:
-            raise BarcodeSizeError("width = %s" % width)
+            raise BarcodeSizeError("width = {width}".format(width=width))
         # Font
         if font.upper() == "B":
             self._raw(BARCODE_FONT_B)
diff --git a/escpos/exceptions.py b/escpos/exceptions.py
index 61319df..e91ed5e 100644
--- a/escpos/exceptions.py
+++ b/escpos/exceptions.py
@@ -46,7 +46,7 @@ class BarcodeTypeError(Error):
         self.resultcode = 10
 
     def __str__(self):
-        return "No Barcode type is defined (%s)" % self.msg
+        return "No Barcode type is defined ({msg})".format(msg=self.msg)
 
 
 class BarcodeSizeError(Error):
@@ -62,7 +62,7 @@ class BarcodeSizeError(Error):
         self.resultcode = 20
 
     def __str__(self):
-        return "Barcode size is out of range (%s)" % self.msg
+        return "Barcode size is out of range ({msg})".format(msg=self.msg)
 
 
 class BarcodeCodeError(Error):
diff --git a/escpos/printer.py b/escpos/printer.py
index f149c2e..7083957 100644
--- a/escpos/printer.py
+++ b/escpos/printer.py
@@ -56,13 +56,13 @@ class Usb(Escpos):
                 self.device.detach_kernel_driver(0)
             except usb.core.USBError as e:
                 if check_driver is not None:
-                    print("Could not detatch kernel driver: %s" % str(e))
+                    print("Could not detatch kernel driver: {0}".format(str(e)))
 
         try:
             self.device.set_configuration()
             self.device.reset()
         except usb.core.USBError as e:
-            print("Could not set configuration: %s" % str(e))
+            print("Could not set configuration: {0}".format(str(e)))
 
     def _raw(self, msg):
         """ Print any command sent in raw format
@@ -120,7 +120,7 @@ class Serial(Escpos):
         if self.device is not None:
             print("Serial printer enabled")
         else:
-            print("Unable to open serial printer on: %s" % self.devfile)
+            print("Unable to open serial printer on: {0}".format(str(self.devfile)))
 
     def _raw(self, msg):
         """ Print any command sent in raw format
@@ -159,7 +159,7 @@ class Network(Escpos):
         self.device.connect((self.host, self.port))
 
         if self.device is None:
-            print("Could not open socket for %s" % self.host)
+            print("Could not open socket for {0}".format(self.host))
 
     def _raw(self, msg):
         """ Print any command sent in raw format
@@ -195,7 +195,7 @@ class File(Escpos):
         self.device = open(self.devfile, "wb")
 
         if self.device is None:
-            print("Could not open the specified file %s" % self.devfile)
+            print("Could not open the specified file {0}".format(self.devfile))
 
     def flush(self):
         """ Flush printing content """