diff --git a/src/calibre/db/cli/cmd_catalog.py b/src/calibre/db/cli/cmd_catalog.py
index a3901180ea..9f75301a64 100644
--- a/src/calibre/db/cli/cmd_catalog.py
+++ b/src/calibre/db/cli/cmd_catalog.py
@@ -43,8 +43,7 @@ def option_parser(get_parser, args):  # {{{
 
     # Entry point
     parser = get_parser(
-        _(
-            '''\
+        _('''\
 %prog catalog /path/to/destination.(csv|epub|mobi|xml...) [options]
 
 Export a catalog in format specified by path/to/destination extension.
@@ -52,8 +51,7 @@ Options control how entries are displayed in the generated catalog output.
 Note that different catalog formats support different sets of options. To
 see the different options, specify the name of the output file and then the
 {} option.
-'''.format('--help')
-        )
+''').format('--help')
     )
 
     # Add options common to all catalog plugins
diff --git a/src/calibre/db/cli/cmd_set_metadata.py b/src/calibre/db/cli/cmd_set_metadata.py
index 3e4b2e8d7d..f537d7f187 100644
--- a/src/calibre/db/cli/cmd_set_metadata.py
+++ b/src/calibre/db/cli/cmd_set_metadata.py
@@ -160,7 +160,7 @@ def main(opts, args, dbctx):
             if field == 'sort':
                 field = 'title_sort'
             if field not in fields:
-                raise SystemExit(_('%s is not a known field' % field))
+                raise SystemExit(_('{} is not a known field'))
             if field == 'cover':
                 val = dbctx.path(os.path.abspath(os.path.expanduser(val)))
             else:
diff --git a/src/calibre/gui2/add.py b/src/calibre/gui2/add.py
index c9af64800a..04c7b0cb22 100644
--- a/src/calibre/gui2/add.py
+++ b/src/calibre/gui2/add.py
@@ -240,7 +240,7 @@ class Adder(QObject):
                     else:
                         a = self.report.append
                         for f in unreadable_files:
-                            a(_('Could not add %s as you do not have permission to read the file' % f))
+                            a(_('Could not add {} as you do not have permission to read the file').format(f))
                             a('')
         except Exception:
             self.scan_error = traceback.format_exc()
diff --git a/src/calibre/gui2/dialogs/custom_recipes.py b/src/calibre/gui2/dialogs/custom_recipes.py
index 091eeb8b3c..764760f781 100644
--- a/src/calibre/gui2/dialogs/custom_recipes.py
+++ b/src/calibre/gui2/dialogs/custom_recipes.py
@@ -435,7 +435,7 @@ class BasicRecipe(QWidget):  # {{{
             compile_recipe(self.recipe_source)
         except Exception as err:
             error_dialog(self, _('Invalid recipe'), _(
-                'Failed to compile the recipe, with syntax error: %s' % err), show=True)
+                'Failed to compile the recipe, with syntax error: {}').format(err), show=True)
             return False
         return True
 
@@ -488,7 +488,7 @@ class AdvancedRecipe(QWidget):  # {{{
             compile_recipe(src)
         except Exception as err:
             error_dialog(self, _('Invalid recipe'), _(
-                'Failed to compile the recipe, with syntax error: %s' % err), show=True)
+                'Failed to compile the recipe, with syntax error: {}' ).format(err), show=True)
             return False
         return True
 
diff --git a/src/calibre/gui2/tweak_book/diff/view.py b/src/calibre/gui2/tweak_book/diff/view.py
index 519b9a3f41..1c3b56fa6f 100644
--- a/src/calibre/gui2/tweak_book/diff/view.py
+++ b/src/calibre/gui2/tweak_book/diff/view.py
@@ -272,7 +272,7 @@ class TextBrowser(PlainTextEdit):  # {{{
             break
         else:
             info_dialog(self, _('No matches found'), _(
-                'No matches found for query: %s' % query), show=True)
+                'No matches found for query: {}').format(query), show=True)
 
     def clear(self):
         PlainTextEdit.clear(self)
diff --git a/src/calibre/gui2/tweak_book/polish.py b/src/calibre/gui2/tweak_book/polish.py
index a1abf6439c..fae596202f 100644
--- a/src/calibre/gui2/tweak_book/polish.py
+++ b/src/calibre/gui2/tweak_book/polish.py
@@ -204,7 +204,7 @@ class LossyCompression(QWidget):
         image_type = image_type.upper()
         self.enable_lossy = el = QCheckBox(_('Enable &lossy compression of {} images').format(image_type))
         el.setToolTip(_('This allows you to change the quality factor used for {} images.\nBy lowering'
-                        ' the quality you can greatly reduce file size, at the expense of the image looking blurred.'.format(image_type)))
+                        ' the quality you can greatly reduce file size, at the expense of the image looking blurred.').format(image_type))
         l.addWidget(el)
         self.h2 = h = QHBoxLayout()
         l.addLayout(h)
diff --git a/src/calibre/library/catalogs/epub_mobi.py b/src/calibre/library/catalogs/epub_mobi.py
index a5ae05c83c..df9b6a7f09 100644
--- a/src/calibre/library/catalogs/epub_mobi.py
+++ b/src/calibre/library/catalogs/epub_mobi.py
@@ -200,8 +200,8 @@ class EPUB_MOBI(CatalogPlugin):
             available_presets = JSONConfig("catalog_presets")
             if opts.preset not in available_presets:
                 if available_presets:
-                    print(_('Error: Preset "%s" not found.' % opts.preset))
-                    print(_('Stored presets: %s' % ', '.join([p for p in sorted(available_presets.keys())])))
+                    print(_('Error: Preset "{}" not found.').format(opts.preset))
+                    print(_('Stored presets: {}').format(', '.join([p for p in sorted(available_presets.keys())])))
                 else:
                     print(_('Error: No stored presets.'))
                 return 1
diff --git a/src/calibre/utils/formatter_functions.py b/src/calibre/utils/formatter_functions.py
index bb78f9a255..4efc91f25c 100644
--- a/src/calibre/utils/formatter_functions.py
+++ b/src/calibre/utils/formatter_functions.py
@@ -2533,8 +2533,7 @@ on a device has its own device name. The ``storage_location_key`` names are
             try:
                 if storage_location not in {'main', 'carda', 'cardb'}:
                     raise ValueError(
-                         _('connected_device_name: invalid storage location "{}"'
-                                    .format(storage_location)))
+                         _('connected_device_name: invalid storage location "{}"').format(storage_location))
                 info = info['info'][4]
                 if storage_location not in info:
                     return ''
@@ -2571,8 +2570,7 @@ only in the GUI.
             try:
                 if storage_location not in {'main', 'carda', 'cardb'}:
                     raise ValueError(
-                         _('connected_device_name: invalid storage location "{}"'
-                                    .format(storage_location)))
+                         _('connected_device_name: invalid storage location "{}"').format(storage_location))
                 info = info['info'][4]
                 if storage_location not in info:
                     return ''