diff --git a/Modules/_ctypes/callbacks.c b/Modules/_ctypes/callbacks.c
index ec9f44336e0e19..5a8303fba290cb 100644
--- a/Modules/_ctypes/callbacks.c
+++ b/Modules/_ctypes/callbacks.c
@@ -160,14 +160,14 @@ static void _CallPythonObject(void *mem,
         if (cnv)
             dict = PyType_stgdict(cnv);
         else {
-            PrintError("Getting argument converter %d\n", i);
+            PrintError("Getting argument converter %zd\n", i);
             goto Done;
         }
 
         if (dict && dict->getfunc && !_ctypes_simple_instance(cnv)) {
             PyObject *v = dict->getfunc(*pArgs, dict->size);
             if (!v) {
-                PrintError("create argument %d:\n", i);
+                PrintError("create argument %zd:\n", i);
                 Py_DECREF(cnv);
                 goto Done;
             }
@@ -181,14 +181,14 @@ static void _CallPythonObject(void *mem,
             /* Hm, shouldn't we use PyCData_AtAddress() or something like that instead? */
             CDataObject *obj = (CDataObject *)_PyObject_CallNoArg(cnv);
             if (!obj) {
-                PrintError("create argument %d:\n", i);
+                PrintError("create argument %zd:\n", i);
                 Py_DECREF(cnv);
                 goto Done;
             }
             if (!CDataObject_Check(obj)) {
                 Py_DECREF(obj);
                 Py_DECREF(cnv);
-                PrintError("unexpected result of create argument %d:\n", i);
+                PrintError("unexpected result of create argument %zd:\n", i);
                 goto Done;
             }
             memcpy(obj->b_ptr, *pArgs, dict->size);
@@ -199,7 +199,7 @@ static void _CallPythonObject(void *mem,
         } else {
             PyErr_SetString(PyExc_TypeError,
                             "cannot build parameter");
-            PrintError("Parsing argument %d\n", i);
+            PrintError("Parsing argument %zd\n", i);
             Py_DECREF(cnv);
             goto Done;
         }
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index e971388f69b92f..ec854c864cc20f 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -1125,20 +1125,20 @@ PyObject *_ctypes_callproc(PPROC pProc,
             converter = PyTuple_GET_ITEM(argtypes, i);
             v = PyObject_CallFunctionObjArgs(converter, arg, NULL);
             if (v == NULL) {
-                _ctypes_extend_error(PyExc_ArgError, "argument %d: ", i+1);
+                _ctypes_extend_error(PyExc_ArgError, "argument %zd: ", i+1);
                 goto cleanup;
             }
 
             err = ConvParam(v, i+1, pa);
             Py_DECREF(v);
             if (-1 == err) {
-                _ctypes_extend_error(PyExc_ArgError, "argument %d: ", i+1);
+                _ctypes_extend_error(PyExc_ArgError, "argument %zd: ", i+1);
                 goto cleanup;
             }
         } else {
             err = ConvParam(arg, i+1, pa);
             if (-1 == err) {
-                _ctypes_extend_error(PyExc_ArgError, "argument %d: ", i+1);
+                _ctypes_extend_error(PyExc_ArgError, "argument %zd: ", i+1);
                 goto cleanup; /* leaking ? */
             }
         }
diff --git a/Modules/_ctypes/malloc_closure.c b/Modules/_ctypes/malloc_closure.c
index 248c6a67022bae..8ad76497c7b3f2 100644
--- a/Modules/_ctypes/malloc_closure.c
+++ b/Modules/_ctypes/malloc_closure.c
@@ -76,7 +76,7 @@ static void more_core(void)
 
 #ifdef MALLOC_CLOSURE_DEBUG
     printf("block at %p allocated (%d bytes), %d ITEMs\n",
-           item, count * sizeof(ITEM), count);
+           item, count * (int)sizeof(ITEM), count);
 #endif
     /* put them into the free list */
     for (i = 0; i < count; ++i) {
diff --git a/Modules/_io/winconsoleio.c b/Modules/_io/winconsoleio.c
index c11c1e09f4c3a1..bf5b10b494744d 100644
--- a/Modules/_io/winconsoleio.c
+++ b/Modules/_io/winconsoleio.c
@@ -724,7 +724,7 @@ readinto(winconsoleio *self, char *buf, Py_ssize_t len)
 
     if (u8n) {
         PyErr_Format(PyExc_SystemError,
-            "Buffer had room for %d bytes but %d bytes required",
+            "Buffer had room for %zd bytes but %u bytes required",
             len, u8n);
         return -1;
     }
diff --git a/Modules/_localemodule.c b/Modules/_localemodule.c
index 8efda35dd4e52a..f9468981185071 100644
--- a/Modules/_localemodule.c
+++ b/Modules/_localemodule.c
@@ -394,7 +394,7 @@ PyLocale_getdefaultlocale(PyObject* self)
     char encoding[100];
     char locale[100];
 
-    PyOS_snprintf(encoding, sizeof(encoding), "cp%d", GetACP());
+    PyOS_snprintf(encoding, sizeof(encoding), "cp%u", GetACP());
 
     if (GetLocaleInfo(LOCALE_USER_DEFAULT,
                       LOCALE_SISO639LANGNAME,
diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
index bb7a7ec50ce059..f93c6c668e5d04 100644
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -219,7 +219,7 @@ parse_filter_spec_lzma(PyObject *spec)
 
     if (lzma_lzma_preset(options, preset)) {
         PyMem_Free(options);
-        PyErr_Format(Error, "Invalid compression preset: %d", preset);
+        PyErr_Format(Error, "Invalid compression preset: %u", preset);
         return NULL;
     }
 
@@ -630,7 +630,7 @@ Compressor_init_alone(lzma_stream *lzs, uint32_t preset, PyObject *filterspecs)
         lzma_options_lzma options;
 
         if (lzma_lzma_preset(&options, preset)) {
-            PyErr_Format(Error, "Invalid compression preset: %d", preset);
+            PyErr_Format(Error, "Invalid compression preset: %u", preset);
             return -1;
         }
         lzret = lzma_alone_encoder(lzs, &options);
diff --git a/Modules/_multiprocessing/semaphore.c b/Modules/_multiprocessing/semaphore.c
index 0cc46b53222ef9..0f3e33d91e9d35 100644
--- a/Modules/_multiprocessing/semaphore.c
+++ b/Modules/_multiprocessing/semaphore.c
@@ -141,7 +141,7 @@ semlock_acquire(SemLockObject *self, PyObject *args, PyObject *kwds)
     default:
         PyErr_Format(PyExc_RuntimeError, "WaitForSingleObject() or "
                      "WaitForMultipleObjects() gave unrecognized "
-                     "value %d", res);
+                     "value %u", res);
         return NULL;
     }
 }
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 9baec8a9bc84e5..7076fddf8dd4d4 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -3348,7 +3348,7 @@ _ssl__SSLContext__set_alpn_protocols_impl(PySSLContext *self,
 #if HAVE_ALPN
     if ((size_t)protos->len > UINT_MAX) {
         PyErr_Format(PyExc_OverflowError,
-            "protocols longer than %d bytes", UINT_MAX);
+            "protocols longer than %u bytes", UINT_MAX);
         return NULL;
     }
 
diff --git a/Modules/binascii.c b/Modules/binascii.c
index d0d3f7d34b8f6a..c13bed6bbfdcae 100644
--- a/Modules/binascii.c
+++ b/Modules/binascii.c
@@ -520,7 +520,7 @@ binascii_a2b_base64_impl(PyObject *module, Py_buffer *data)
             */
             PyErr_Format(Error,
                          "Invalid base64-encoded string: "
-                         "number of data characters (%d) cannot be 1 more "
+                         "number of data characters (%zd) cannot be 1 more "
                          "than a multiple of 4",
                          (bin_data - bin_data_start) / 3 * 4 + 1);
         } else {
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 988471e15fbe30..65385e8974cf9c 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -4102,7 +4102,7 @@ sock_sendto(PySocketSockObject *s, PyObject *args)
             break;
         default:
             PyErr_Format(PyExc_TypeError,
-                         "sendto() takes 2 or 3 arguments (%d given)",
+                         "sendto() takes 2 or 3 arguments (%zd given)",
                          arglen);
             return NULL;
     }
@@ -4642,7 +4642,7 @@ sock_ioctl(PySocketSockObject *s, PyObject *arg)
         return PyLong_FromUnsignedLong(recv); }
 #endif
     default:
-        PyErr_Format(PyExc_ValueError, "invalid ioctl command %d", cmd);
+        PyErr_Format(PyExc_ValueError, "invalid ioctl command %lu", cmd);
         return NULL;
     }
 }
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 172c7f38b9e258..a5319da48daab3 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -1209,7 +1209,7 @@ PyObject *_PyBytes_DecodeEscape(const char *s,
 
             if (!errors || strcmp(errors, "strict") == 0) {
                 PyErr_Format(PyExc_ValueError,
-                             "invalid \\x escape at position %d",
+                             "invalid \\x escape at position %zd",
                              s - 2 - (end - len));
                 goto failed;
             }
diff --git a/Objects/odictobject.c b/Objects/odictobject.c
index 7487bd96076420..88afc61f6071da 100644
--- a/Objects/odictobject.c
+++ b/Objects/odictobject.c
@@ -1538,7 +1538,7 @@ odict_init(PyObject *self, PyObject *args, PyObject *kwds)
     if (len == -1)
         return -1;
     if (len > 1) {
-        const char *msg = "expected at most 1 arguments, got %d";
+        const char *msg = "expected at most 1 arguments, got %zd";
         PyErr_Format(PyExc_TypeError, msg, len);
         return -1;
     }
@@ -2211,7 +2211,7 @@ mutablemapping_update(PyObject *self, PyObject *args, PyObject *kwargs)
     assert(args == NULL || PyTuple_Check(args));
     len = (args != NULL) ? PyTuple_GET_SIZE(args) : 0;
     if (len > 1) {
-        const char *msg = "update() takes at most 1 positional argument (%d given)";
+        const char *msg = "update() takes at most 1 positional argument (%zd given)";
         PyErr_Format(PyExc_TypeError, msg, len);
         return NULL;
     }
diff --git a/Objects/structseq.c b/Objects/structseq.c
index 1b71f724a66b09..900aaba7c150cb 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -194,7 +194,7 @@ structseq_repr(PyStructSequence *obj)
 
         cname = typ->tp_members[i].name;
         if (cname == NULL) {
-            PyErr_Format(PyExc_SystemError, "In structseq_repr(), member %d name is NULL"
+            PyErr_Format(PyExc_SystemError, "In structseq_repr(), member %zd name is NULL"
                          " for type %.500s", i, typ->tp_name);
             return NULL;
         }
diff --git a/PC/launcher.c b/PC/launcher.c
index a4e678115f3470..0f5003a8370e59 100644
--- a/PC/launcher.c
+++ b/PC/launcher.c
@@ -718,7 +718,7 @@ invoke_child(wchar_t * executable, wchar_t * suffix, wchar_t * cmdline)
         }
         child_command = calloc(child_command_size, sizeof(wchar_t));
         if (child_command == NULL)
-            error(RC_CREATE_PROCESS, L"unable to allocate %d bytes for child command.",
+            error(RC_CREATE_PROCESS, L"unable to allocate %zd bytes for child command.",
                   child_command_size);
         if (no_suffix)
             _snwprintf_s(child_command, child_command_size,
@@ -1189,7 +1189,7 @@ maybe_handle_shebang(wchar_t ** argv, wchar_t * cmdline)
 
     if (rc == 0) {
         read = fread(buffer, sizeof(char), BUFSIZE, fp);
-        debug(L"maybe_handle_shebang: read %d bytes\n", read);
+        debug(L"maybe_handle_shebang: read %zd bytes\n", read);
         fclose(fp);
 
         if ((read >= 4) && (buffer[3] == '\n') && (buffer[2] == '\r')) {
@@ -1209,7 +1209,7 @@ maybe_handle_shebang(wchar_t ** argv, wchar_t * cmdline)
             bom = BOMs; /* points to UTF-8 entry - the default */
         }
         else {
-            debug(L"maybe_handle_shebang: BOM found, code page %d\n",
+            debug(L"maybe_handle_shebang: BOM found, code page %u\n",
                   bom->code_page);
             start = &buffer[bom->length];
         }
diff --git a/Python/dynload_win.c b/Python/dynload_win.c
index 0fdf77f55280ca..51325be658af88 100644
--- a/Python/dynload_win.c
+++ b/Python/dynload_win.c
@@ -254,7 +254,7 @@ dl_funcptr _PyImport_FindSharedFuncptrWindows(const char *prefix,
                This should not happen if called correctly. */
             if (theLength == 0) {
                 message = PyUnicode_FromFormat(
-                    "DLL load failed with error code %d",
+                    "DLL load failed with error code %u",
                     errorCode);
             } else {
                 /* For some reason a \r\n
diff --git a/Python/getargs.c b/Python/getargs.c
index 992cb216c257f9..73e47f84561b87 100644
--- a/Python/getargs.c
+++ b/Python/getargs.c
@@ -371,14 +371,14 @@ vgetargs1_impl(PyObject *compat_args, PyObject *const *stack, Py_ssize_t nargs,
     if (nargs < min || max < nargs) {
         if (message == NULL)
             PyErr_Format(PyExc_TypeError,
-                         "%.150s%s takes %s %d argument%s (%ld given)",
+                         "%.150s%s takes %s %d argument%s (%zd given)",
                          fname==NULL ? "function" : fname,
                          fname==NULL ? "" : "()",
                          min==max ? "exactly"
                          : nargs < min ? "at least" : "at most",
                          nargs < min ? min : max,
                          (nargs < min ? min : max) == 1 ? "" : "s",
-                         Py_SAFE_DOWNCAST(nargs, Py_ssize_t, long));
+                         nargs);
         else
             PyErr_SetString(PyExc_TypeError, message);
         return cleanreturn(0, &freelist);
@@ -1718,7 +1718,7 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
                 else {
                     PyErr_Format(PyExc_TypeError,
                                  "%.200s%s takes %s %d positional arguments"
-                                 " (%d given)",
+                                 " (%zd given)",
                                  (fname == NULL) ? "function" : fname,
                                  (fname == NULL) ? "" : "()",
                                  (min != INT_MAX) ? "at most" : "exactly",
@@ -1797,7 +1797,7 @@ vgetargskeywords(PyObject *args, PyObject *kwargs, const char *format,
     if (skip) {
         PyErr_Format(PyExc_TypeError,
                      "%.200s%s takes %s %d positional arguments"
-                     " (%d given)",
+                     " (%zd given)",
                      (fname == NULL) ? "function" : fname,
                      (fname == NULL) ? "" : "()",
                      (Py_MIN(pos, min) < i) ? "at least" : "exactly",
@@ -2103,7 +2103,7 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
         }
         else {
             PyErr_Format(PyExc_TypeError,
-                         "%.200s%s takes %s %d positional arguments (%d given)",
+                         "%.200s%s takes %s %d positional arguments (%zd given)",
                          (parser->fname == NULL) ? "function" : parser->fname,
                          (parser->fname == NULL) ? "" : "()",
                          (parser->min != INT_MAX) ? "at most" : "exactly",
@@ -2152,7 +2152,7 @@ vgetargskeywordsfast_impl(PyObject *const *args, Py_ssize_t nargs,
                 Py_ssize_t min = Py_MIN(pos, parser->min);
                 PyErr_Format(PyExc_TypeError,
                              "%.200s%s takes %s %d positional arguments"
-                             " (%d given)",
+                             " (%zd given)",
                              (parser->fname == NULL) ? "function" : parser->fname,
                              (parser->fname == NULL) ? "" : "()",
                              min < parser->max ? "at least" : "exactly",
diff --git a/Python/hamt.c b/Python/hamt.c
index 562f777ea0bf86..71a5ec87c5856a 100644
--- a/Python/hamt.c
+++ b/Python/hamt.c
@@ -2003,7 +2003,7 @@ hamt_node_array_dump(PyHamtNode_Array *node,
             goto error;
         }
 
-        if (_hamt_dump_format(writer, "%d::\n", i)) {
+        if (_hamt_dump_format(writer, "%zd::\n", i)) {
             goto error;
         }
 
diff --git a/Python/pyarena.c b/Python/pyarena.c
index 103603fcdff32e..d2aa8b8c3264dc 100644
--- a/Python/pyarena.c
+++ b/Python/pyarena.c
@@ -160,7 +160,7 @@ PyArena_Free(PyArena *arena)
 #if defined(Py_DEBUG)
     /*
     fprintf(stderr,
-        "alloc=%d size=%d blocks=%d block_size=%d big=%d objects=%d\n",
+        "alloc=%zu size=%zu blocks=%zu block_size=%zu big=%zu objects=%zu\n",
         arena->total_allocs, arena->total_size, arena->total_blocks,
         arena->total_block_size, arena->total_big_blocks,
         PyList_Size(arena->a_objects));