diff --git a/pylib/anki/db.py b/pylib/anki/db.py
index eebc5be67..ae5d55eac 100644
--- a/pylib/anki/db.py
+++ b/pylib/anki/db.py
@@ -47,7 +47,7 @@ class DB:
             res = self._db.execute(sql, a)
         if self.echo:
             # print a, ka
-            print(sql, "%0.3fms" % ((time.time() - t) * 1000))
+            print(sql, f"{(time.time() - t) * 1000:0.3f}ms")
             if self.echo == "2":
                 print(a, ka)
         return res
@@ -57,7 +57,7 @@ class DB:
         t = time.time()
         self._db.executemany(sql, l)
         if self.echo:
-            print(sql, "%0.3fms" % ((time.time() - t) * 1000))
+            print(sql, f"{(time.time() - t) * 1000:0.3f}ms")
             if self.echo == "2":
                 print(l)
 
@@ -65,7 +65,7 @@ class DB:
         t = time.time()
         self._db.commit()
         if self.echo:
-            print("commit %0.3fms" % ((time.time() - t) * 1000))
+            print(f"commit {(time.time() - t) * 1000:0.3f}ms")
 
     def executescript(self, sql: str) -> None:
         self.mod = True
diff --git a/pylib/anki/decks.py b/pylib/anki/decks.py
index a102a2145..b40216b48 100644
--- a/pylib/anki/decks.py
+++ b/pylib/anki/decks.py
@@ -234,9 +234,9 @@ class DeckManager(DeprecatedNamesMixin):
             dids = set(dids)
         if include_subdecks:
             dids.update([child[1] for did in dids for child in self.children(did)])
+        str_ids = ids2str(dids)
         count = self.col.db.scalar(
-            "select count() from cards where did in {0} or "
-            "odid in {0}".format(ids2str(dids))
+            f"select count() from cards where did in {str_ids} or odid in {str_ids}"
         )
         return count
 
diff --git a/pylib/anki/importing/mnemo.py b/pylib/anki/importing/mnemo.py
index cc508552c..fb1305da7 100644
--- a/pylib/anki/importing/mnemo.py
+++ b/pylib/anki/importing/mnemo.py
@@ -149,7 +149,7 @@ acq_reps+ret_reps, lapses, card_type_id from cards"""
         mm = self.col.models
         t = mm.new_template("Back")
         t["qfmt"] = "{{Back}}"
-        t["afmt"] = t["qfmt"] + "\n\n<hr id=answer>\n\n{{Front}}"  # type: ignore
+        t["afmt"] = f"{t['qfmt']}\n\n<hr id=answer>\n\n{{{{Front}}}}"  # type: ignore
         mm.add_template(m, t)
         self._addFronts(notes, m)
 
@@ -161,19 +161,15 @@ acq_reps+ret_reps, lapses, card_type_id from cards"""
             mm.addField(m, fm)
         t = mm.new_template("Recognition")
         t["qfmt"] = "{{Expression}}"
-        t["afmt"] = (
-            cast(str, t["qfmt"])
-            + """\n\n<hr id=answer>\n\n\
-{{Pronunciation}}<br>\n{{Meaning}}<br>\n{{Notes}}"""
-        )
+        t[
+            "afmt"
+        ] = f"{cast(str, t['qfmt'])}\n\n<hr id=answer>\n\n{{{{Pronunciation}}}}<br>\n{{{{Meaning}}}}<br>\n{{{{Notes}}}}"
         mm.add_template(m, t)
         t = mm.new_template("Production")
         t["qfmt"] = "{{Meaning}}"
-        t["afmt"] = (
-            cast(str, t["qfmt"])
-            + """\n\n<hr id=answer>\n\n\
-{{Expression}}<br>\n{{Pronunciation}}<br>\n{{Notes}}"""
-        )
+        t[
+            "afmt"
+        ] = f"{cast(str, t['qfmt'])}\n\n<hr id=answer>\n\n{{{{Expression}}}}<br>\n{{{{Pronunciation}}}}<br>\n{{{{Notes}}}}"
         mm.add_template(m, t)
         mm.add(m)
         self._addFronts(notes, m, fields=("f", "p_1", "m_1", "n"))
diff --git a/pylib/anki/models.py b/pylib/anki/models.py
index 932b461c1..1f172f9b8 100644
--- a/pylib/anki/models.py
+++ b/pylib/anki/models.py
@@ -214,7 +214,7 @@ class ModelManager(DeprecatedNamesMixin):
     def ensure_name_unique(self, notetype: NotetypeDict) -> None:
         existing_id = self.id_for_name(notetype["name"])
         if existing_id is not None and existing_id != notetype["id"]:
-            notetype["name"] += "-" + checksum(str(time.time()))[:5]
+            notetype["name"] += f"-{checksum(str(time.time()))[:5]}"
 
     def update_dict(self, notetype: NotetypeDict) -> OpChanges:
         "Update a NotetypeDict. Caller will need to re-load notetype if new fields/cards added."
diff --git a/pylib/anki/scheduler/legacy.py b/pylib/anki/scheduler/legacy.py
index c289400c3..85afb717d 100644
--- a/pylib/anki/scheduler/legacy.py
+++ b/pylib/anki/scheduler/legacy.py
@@ -71,10 +71,9 @@ else
 end)
 """
         self.col.db.execute(
-            """
-update cards set did = odid, %s,
-due = (case when odue>0 then odue else due end), odue = 0, odid = 0, usn = ? where %s"""
-            % (queue, lim),
+            f"""
+update cards set did = odid, {queue},
+due = (case when odue>0 then odue else due end), odue = 0, odid = 0, usn = ? where {lim}""",
             self.col.usn(),
         )
 
diff --git a/pylib/anki/scheduler/v1.py b/pylib/anki/scheduler/v1.py
index adbd7a177..0a4ddccc3 100644
--- a/pylib/anki/scheduler/v1.py
+++ b/pylib/anki/scheduler/v1.py
@@ -381,9 +381,7 @@ limit %d"""
         else:
             # benchmarks indicate it's about 10x faster to search all decks
             # with the index than scan the table
-            extra = " and did in " + ids2str(
-                d.id for d in self.col.decks.all_names_and_ids()
-            )
+            extra = f" and did in {ids2str(d.id for d in self.col.decks.all_names_and_ids())}"
         # review cards in relearning
         self.col.db.execute(
             f"""
diff --git a/pylib/anki/scheduler/v2.py b/pylib/anki/scheduler/v2.py
index 1eddef19b..750bb4635 100644
--- a/pylib/anki/scheduler/v2.py
+++ b/pylib/anki/scheduler/v2.py
@@ -1141,7 +1141,7 @@ and (queue={QUEUE_TYPE_NEW} or (queue={QUEUE_TYPE_REV} and due<=?))""",
             return self.col.tr.scheduling_end()
         s = self.col.format_timespan(ivl_secs, FormatTimeSpan.ANSWER_BUTTONS)
         if ivl_secs < self.col.conf["collapseTime"]:
-            s = "<" + s
+            s = f"<{s}"
         return s
 
     def _is_finished(self) -> bool:
diff --git a/pylib/anki/utils.py b/pylib/anki/utils.py
index 53a573c7a..e59629af0 100644
--- a/pylib/anki/utils.py
+++ b/pylib/anki/utils.py
@@ -91,7 +91,7 @@ def htmlToTextLine(s: str) -> str:
 
 def ids2str(ids: Iterable[Union[int, str]]) -> str:
     """Given a list of integers, return a string '(int1,int2,...)'."""
-    return "(%s)" % ",".join(str(i) for i in ids)
+    return f"({','.join(str(i) for i in ids)})"
 
 
 def timestampID(db: DBProxy, table: str) -> int:
diff --git a/pylib/tests/run_mypy.py b/pylib/tests/run_mypy.py
index 122b3a08d..fc5194a89 100644
--- a/pylib/tests/run_mypy.py
+++ b/pylib/tests/run_mypy.py
@@ -32,7 +32,7 @@ if __name__ == "__main__":
         # strip off prefix
         for entry in sys.path:
             if "__mypy_" in entry:
-                typeshed = entry[4:] + "\\mypy\\typeshed"
+                typeshed = f"{entry[4:]}\\mypy\\typeshed"
                 args.append("--custom-typeshed-dir")
                 args.append(typeshed)
 
diff --git a/pylib/tests/test_importing.py b/pylib/tests/test_importing.py
index 40dc4d7c5..7cc5a4f6b 100644
--- a/pylib/tests/test_importing.py
+++ b/pylib/tests/test_importing.py
@@ -63,7 +63,7 @@ def test_anki2_mediadupes():
         note.write("bar")
     imp = Anki2Importer(empty, col.path)
     imp.run()
-    assert sorted(os.listdir(empty.media.dir())) == ["foo.mp3", "foo_%s.mp3" % mid]
+    assert sorted(os.listdir(empty.media.dir())) == ["foo.mp3", f"foo_{mid}.mp3"]
     n = empty.get_note(empty.db.scalar("select id from notes"))
     assert "_" in n.fields[0]
     # if the localized media file already exists, we rewrite the note and
@@ -73,8 +73,8 @@ def test_anki2_mediadupes():
         note.write("bar")
     imp = Anki2Importer(empty, col.path)
     imp.run()
-    assert sorted(os.listdir(empty.media.dir())) == ["foo.mp3", "foo_%s.mp3" % mid]
-    assert sorted(os.listdir(empty.media.dir())) == ["foo.mp3", "foo_%s.mp3" % mid]
+    assert sorted(os.listdir(empty.media.dir())) == ["foo.mp3", f"foo_{mid}.mp3"]
+    assert sorted(os.listdir(empty.media.dir())) == ["foo.mp3", f"foo_{mid}.mp3"]
     n = empty.get_note(empty.db.scalar("select id from notes"))
     assert "_" in n.fields[0]
 
diff --git a/pylib/tests/test_latex.py b/pylib/tests/test_latex.py
index 5ad4b3529..89c8229a3 100644
--- a/pylib/tests/test_latex.py
+++ b/pylib/tests/test_latex.py
@@ -93,7 +93,7 @@ def test_latex():
 def _test_includes_bad_command(bad):
     col = getEmptyCol()
     note = col.newNote()
-    note["Front"] = "[latex]%s[/latex]" % bad
+    note["Front"] = f"[latex]{bad}[/latex]"
     col.addNote(note)
     q = without_unicode_isolation(note.cards()[0].question())
-    return ("'%s' is not allowed on cards" % bad in q, "Card content: %s" % q)
+    return (f"'{bad}' is not allowed on cards" in q, f"Card content: {q}")
diff --git a/pylib/tests/test_schedv1.py b/pylib/tests/test_schedv1.py
index 056d49c69..77fb7c06f 100644
--- a/pylib/tests/test_schedv1.py
+++ b/pylib/tests/test_schedv1.py
@@ -910,7 +910,7 @@ def test_timing():
     # add a few review cards, due today
     for i in range(5):
         note = col.newNote()
-        note["Front"] = "num" + str(i)
+        note["Front"] = f"num{str(i)}"
         col.addNote(note)
         c = note.cards()[0]
         c.type = CARD_TYPE_REV
diff --git a/pylib/tests/test_schedv2.py b/pylib/tests/test_schedv2.py
index e374d733a..fbf5cbb0c 100644
--- a/pylib/tests/test_schedv2.py
+++ b/pylib/tests/test_schedv2.py
@@ -1019,7 +1019,7 @@ def test_timing():
     # add a few review cards, due today
     for i in range(5):
         note = col.newNote()
-        note["Front"] = "num" + str(i)
+        note["Front"] = f"num{str(i)}"
         col.addNote(note)
         c = note.cards()[0]
         c.type = CARD_TYPE_REV
diff --git a/pylib/tools/hookslib.py b/pylib/tools/hookslib.py
index 1628d4929..c4331b22b 100644
--- a/pylib/tools/hookslib.py
+++ b/pylib/tools/hookslib.py
@@ -36,7 +36,7 @@ class Hook:
         types = []
         for arg in self.args or []:
             (name, type) = arg.split(":")
-            type = '"' + type.strip() + '"'
+            type = f'"{type.strip()}"'
             types.append(type)
         types_str = ", ".join(types)
         return f"Callable[[{types_str}], {self.return_type or 'None'}]"
@@ -60,7 +60,7 @@ class Hook:
             return "hook"
 
     def classname(self) -> str:
-        return "_" + stringcase.pascalcase(self.full_name())
+        return f"_{stringcase.pascalcase(self.full_name())}"
 
     def list_code(self) -> str:
         return f"""\
@@ -126,7 +126,7 @@ class {self.classname()}:
         # legacy support
         anki.hooks.runHook({self.legacy_args()})
 """
-        return out + "\n\n"
+        return f"{out}\n\n"
 
     def filter_fire_code(self) -> str:
         arg_names = self.arg_names()
@@ -150,16 +150,16 @@ class {self.classname()}:
         out += f"""\
         return {arg_names[0]}
 """
-        return out + "\n\n"
+        return f"{out}\n\n"
 
 
 def write_file(path: str, hooks: List[Hook], prefix: str, suffix: str):
     hooks.sort(key=attrgetter("name"))
-    code = prefix + "\n"
+    code = f"{prefix}\n"
     for hook in hooks:
         code += hook.code()
 
-    code += "\n" + suffix
+    code += f"\n{suffix}"
 
     # work around issue with latest black
     if sys.platform == "win32" and "HOME" in os.environ:
diff --git a/pylib/tools/protoc_wrapper.py b/pylib/tools/protoc_wrapper.py
index f10af3464..42c1dc3d8 100644
--- a/pylib/tools/protoc_wrapper.py
+++ b/pylib/tools/protoc_wrapper.py
@@ -21,11 +21,11 @@ else:
 subprocess.run(
     [
         protoc,
-        "--plugin=protoc-gen-mypy=" + mypy_protobuf,
+        f"--plugin=protoc-gen-mypy={mypy_protobuf}",
         "--python_out=.",
         "--mypy_out=.",
-        "-I" + prefix,
-        "-Iexternal/ankidesktop/" + prefix,
+        f"-I{prefix}",
+        f"-Iexternal/ankidesktop/{prefix}",
         *protos,
     ],
     # mypy prints to stderr on success :-(