diff --git a/psutil/__init__.py b/psutil/__init__.py
index d4d08df8c..160c813d8 100644
--- a/psutil/__init__.py
+++ b/psutil/__init__.py
@@ -420,7 +420,7 @@ def __str__(self):
             return "%s.%s(%s)" % (
                 self.__class__.__module__,
                 self.__class__.__name__,
-                ", ".join(["%s=%r" % (k, v) for k, v in info.items()]),
+                ", ".join([f"{k}={v!r}" for k, v in info.items()]),
             )
 
     __repr__ = __str__
@@ -1176,7 +1176,7 @@ def memory_percent(self, memtype="rss"):
             # we should never get here
             msg = (
                 "can't calculate process memory percent because total physical"
-                " system memory is not positive (%r)" % (total_phymem)
+                f" system memory is not positive ({total_phymem!r})"
             )
             raise ValueError(msg)
         return (value / float(total_phymem)) * 100
diff --git a/psutil/_common.py b/psutil/_common.py
index c0b84b923..1e8bb7959 100644
--- a/psutil/_common.py
+++ b/psutil/_common.py
@@ -863,9 +863,8 @@ def hilite(s, color=None, bold=False):  # pragma: no cover
     try:
         color = colors[color]
     except KeyError:
-        raise ValueError(
-            "invalid color %r; choose between %s" % (list(colors.keys()))
-        )
+        msg = f"invalid color {color!r}; choose amongst {list(colors.keys())}"
+        raise ValueError(msg)
     attr.append(color)
     if bold:
         attr.append('1')
diff --git a/psutil/_psbsd.py b/psutil/_psbsd.py
index aa033bb36..6f6eeb35f 100644
--- a/psutil/_psbsd.py
+++ b/psutil/_psbsd.py
@@ -964,9 +964,10 @@ def rlimit(self, resource, limits=None):
                 return cext.proc_getrlimit(self.pid, resource)
             else:
                 if len(limits) != 2:
-                    raise ValueError(
-                        "second argument must be a (soft, hard) tuple, got %s"
-                        % repr(limits)
+                    msg = (
+                        "second argument must be a (soft, hard) tuple, got"
+                        f" {limits!r}"
                     )
+                    raise ValueError(msg)
                 soft, hard = limits
                 return cext.proc_setrlimit(self.pid, resource, soft, hard)
diff --git a/psutil/_pslinux.py b/psutil/_pslinux.py
index 1202c0cbd..531503d55 100644
--- a/psutil/_pslinux.py
+++ b/psutil/_pslinux.py
@@ -324,9 +324,8 @@ def calculate_avail_vmem(mems):
         slab_reclaimable = mems[b'SReclaimable:']
     except KeyError as err:
         debug(
-            "%s is missing from /proc/meminfo; using an approximation for "
-            "calculating available memory"
-            % err.args[0]
+            f"{err.args[0]} is missing from /proc/meminfo; using an"
+            " approximation for calculating available memory"
         )
         return fallback
     try:
@@ -1149,11 +1148,11 @@ def read_sysfs():
     elif os.path.exists('/sys/block'):
         gen = read_sysfs()
     else:
-        raise NotImplementedError(
-            "%s/diskstats nor /sys/block filesystem are available on this "
-            "system"
-            % get_procfs_path()
+        msg = (
+            f"{get_procfs_path()}/diskstats nor /sys/block are available on"
+            " this system"
         )
+        raise NotImplementedError(msg)
 
     retdict = {}
     for entry in gen:
@@ -1856,10 +1855,11 @@ def io_counters(self):
                     fields[b'wchar'],  # write chars
                 )
             except KeyError as err:
-                raise ValueError(
-                    "%r field was not found in %s; found fields are %r"
-                    % (err.args[0], fname, fields)
+                msg = (
+                    f"{err.args[0]!r} field was not found in {fname}; found"
+                    f" fields are {fields!r}"
                 )
+                raise ValueError(msg)
 
     @wrap_exceptions
     def cpu_times(self):
@@ -2068,11 +2068,13 @@ def num_ctx_switches(
         data = self._read_status_file()
         ctxsw = _ctxsw_re.findall(data)
         if not ctxsw:
-            raise NotImplementedError(
-                "'voluntary_ctxt_switches' and 'nonvoluntary_ctxt_switches'"
-                "lines were not found in %s/%s/status; the kernel is "
-                "probably older than 2.6.23" % (self._procfs_path, self.pid)
+            msg = (
+                "'voluntary_ctxt_switches' and"
+                " 'nonvoluntary_ctxt_switches'lines were not found in"
+                f" {self._procfs_path}/{self.pid}/status; the kernel is"
+                " probably older than 2.6.23"
             )
+            raise NotImplementedError(msg)
         else:
             return _common.pctxsw(int(ctxsw[0]), int(ctxsw[1]))
 
diff --git a/psutil/tests/__init__.py b/psutil/tests/__init__.py
index 455936847..c852ead0a 100644
--- a/psutil/tests/__init__.py
+++ b/psutil/tests/__init__.py
@@ -289,7 +289,7 @@ def __init__(self):
 
     def __repr__(self):
         name = self.__class__.__name__
-        return '<%s running=%s at %#x>' % (name, self._running, id(self))
+        return f"<{name} running={self._running} at {id(self):#x}>"
 
     def __enter__(self):
         self.start()
@@ -391,16 +391,16 @@ def spawn_children_pair():
     tfile = None
     testfn = get_testfn(dir=os.getcwd())
     try:
-        s = textwrap.dedent("""\
+        s = textwrap.dedent(f"""\
             import subprocess, os, sys, time
             s = "import os, time;"
-            s += "f = open('%s', 'w');"
+            s += "f = open('{os.path.basename(testfn)}', 'w');"
             s += "f.write(str(os.getpid()));"
             s += "f.close();"
             s += "[time.sleep(0.1) for x in range(100 * 6)];"
-            p = subprocess.Popen([r'%s', '-c', s])
+            p = subprocess.Popen([r'{PYTHON_EXE}', '-c', s])
             p.wait()
-            """ % (os.path.basename(testfn), PYTHON_EXE))
+            """)
         # On Windows if we create a subprocess with CREATE_NO_WINDOW flag
         # set (which is the default) a "conhost.exe" extra process will be
         # spawned as a child. We don't want that.
@@ -1179,10 +1179,11 @@ def _check_fds(self, fun):
         after = self._get_num_fds()
         diff = after - before
         if diff < 0:
-            raise self.fail(
-                "negative diff %r (gc probably collected a "
-                "resource from a previous test)" % diff
+            msg = (
+                f"negative diff {diff!r} (gc probably collected a"
+                " resource from a previous test)"
             )
+            raise self.fail(msg)
         if diff > 0:
             type_ = "fd" if POSIX else "handle"
             if diff > 1:
@@ -1526,9 +1527,9 @@ def test_class_coverage(cls, test_class, ls):
         for fun_name, _, _ in ls:
             meth_name = 'test_' + fun_name
             if not hasattr(test_class, meth_name):
-                msg = "%r class should define a '%s' method" % (
-                    test_class.__class__.__name__,
-                    meth_name,
+                msg = (
+                    f"{test_class.__class__.__name__!r} class should define a"
+                    f" {meth_name!r} method"
                 )
                 raise AttributeError(msg)
 
@@ -1657,8 +1658,8 @@ def wrapper(*args, **kwargs):
                     if not only_if:
                         raise
                 msg = (
-                    "%r was skipped because it raised NotImplementedError"
-                    % fun.__name__
+                    f"{fun.__name__!r} was skipped because it raised"
+                    " NotImplementedError"
                 )
                 raise pytest.skip(msg)
 
diff --git a/psutil/tests/test_aix.py b/psutil/tests/test_aix.py
index 2b0f849be..10934c12d 100755
--- a/psutil/tests/test_aix.py
+++ b/psutil/tests/test_aix.py
@@ -31,7 +31,7 @@ def test_virtual_memory(self):
             "available",
             "mmode",
         ]:
-            re_pattern += r"(?P<%s>\S+)\s+" % (field,)
+            re_pattern += rf"(?P<{field}>\S+)\s+"
         matchobj = re.search(re_pattern, out)
 
         assert matchobj is not None
@@ -104,7 +104,7 @@ def test_cpu_stats(self):
             "S5rd",
             "sysc",
         ]:
-            re_pattern += r"(?P<%s>\S+)\s+" % (field,)
+            re_pattern += rf"(?P<{field}>\S+)\s+"
         matchobj = re.search(re_pattern, out)
 
         assert matchobj is not None
diff --git a/psutil/tests/test_connections.py b/psutil/tests/test_connections.py
index 47f69fed5..a082f9015 100755
--- a/psutil/tests/test_connections.py
+++ b/psutil/tests/test_connections.py
@@ -522,14 +522,14 @@ def test_multi_sockets_procs(self):
         for _ in range(times):
             fname = self.get_testfn()
             fnames.append(fname)
-            src = textwrap.dedent("""\
+            src = textwrap.dedent(f"""\
                 import time, os
                 from psutil.tests import create_sockets
                 with create_sockets():
-                    with open(r'%s', 'w') as f:
+                    with open(r'{fname}', 'w') as f:
                         f.write("hello")
                     [time.sleep(0.1) for x in range(100)]
-                """ % fname)
+                """)
             sproc = self.pyrun(src)
             pids.append(sproc.pid)
 
diff --git a/psutil/tests/test_linux.py b/psutil/tests/test_linux.py
index 5719868ec..4c36d27d8 100755
--- a/psutil/tests/test_linux.py
+++ b/psutil/tests/test_linux.py
@@ -146,7 +146,7 @@ def free_swap():
             nt = collections.namedtuple('free', 'total used free')
             return nt(int(total), int(used), int(free))
     raise ValueError(
-        "can't find 'Swap' in 'free' output:\n%s" % '\n'.join(lines)
+        f"can't find 'Swap' in 'free' output:\n{'\n'.join(lines)}"
     )
 
 
@@ -167,9 +167,7 @@ def free_physmem():
                 'free', 'total used free shared output'
             )
             return nt(total, used, free, shared, out)
-    raise ValueError(
-        "can't find 'Mem' in 'free' output:\n%s" % '\n'.join(lines)
-    )
+    raise ValueError(f"can't find 'Mem' in 'free' output:\n{'\n'.join(lines)}")
 
 
 def vmstat(stat):
diff --git a/psutil/tests/test_misc.py b/psutil/tests/test_misc.py
index fdfc72696..9d24bb32c 100755
--- a/psutil/tests/test_misc.py
+++ b/psutil/tests/test_misc.py
@@ -941,8 +941,8 @@ def test_coverage(self):
                 if 'test_' + os.path.splitext(name)[0] not in meths:
                     # self.assert_stdout(name)
                     raise self.fail(
-                        'no test defined for %r script'
-                        % os.path.join(SCRIPTS_DIR, name)
+                        "no test defined for"
+                        f" {os.path.join(SCRIPTS_DIR, name)!r} script"
                     )
 
     @pytest.mark.skipif(not POSIX, reason="POSIX only")
diff --git a/psutil/tests/test_process.py b/psutil/tests/test_process.py
index db1dcda71..45129ddca 100755
--- a/psutil/tests/test_process.py
+++ b/psutil/tests/test_process.py
@@ -1072,8 +1072,8 @@ def test_open_files(self):
 
         # another process
         cmdline = (
-            "import time; f = open(r'%s', 'r'); [time.sleep(0.1) for x in"
-            " range(100)];" % testfn
+            f"import time; f = open(r'{testfn}', 'r'); [time.sleep(0.1) for x"
+            " in range(100)];"
         )
         p = self.spawn_psproc([PYTHON_EXE, "-c", cmdline])
 
diff --git a/scripts/internal/bench_oneshot.py b/scripts/internal/bench_oneshot.py
index 090237539..299f9cea6 100755
--- a/scripts/internal/bench_oneshot.py
+++ b/scripts/internal/bench_oneshot.py
@@ -126,8 +126,9 @@ def call_oneshot(funs):
 
 def main():
     print(
-        "%s methods involved on platform %r (%s iterations, psutil %s):"
-        % (len(names), sys.platform, ITERATIONS, psutil.__version__)
+        f"{len(names)} methods involved on platform"
+        f" {sys.platform!r} ({ITERATIONS} iterations, psutil"
+        f" {psutil.__version__}):"
     )
     for name in sorted(names):
         print("    " + name)
diff --git a/scripts/internal/bench_oneshot_2.py b/scripts/internal/bench_oneshot_2.py
index 41c9cbb89..1076dffc8 100755
--- a/scripts/internal/bench_oneshot_2.py
+++ b/scripts/internal/bench_oneshot_2.py
@@ -37,8 +37,8 @@ def main():
     args = runner.parse_args()
     if not args.worker:
         print(
-            "%s methods involved on platform %r (psutil %s):"
-            % (len(names), sys.platform, psutil.__version__)
+            f"{len(names)} methods involved on platform"
+            f" {sys.platform!r} (psutil {psutil.__version__}):"
         )
         for name in sorted(names):
             print("    " + name)
diff --git a/scripts/internal/winmake.py b/scripts/internal/winmake.py
index 2267ce410..5413b827b 100755
--- a/scripts/internal/winmake.py
+++ b/scripts/internal/winmake.py
@@ -467,7 +467,7 @@ def get_python(path):
         '312-64',
     )
     for v in vers:
-        pypath = r'C:\\python%s\python.exe' % v
+        pypath = rf"C:\\python{v}\python.exe"
         if path in pypath and os.path.isfile(pypath):
             return pypath