diff --git a/dlls/secur32/tests/ntlm.c b/dlls/secur32/tests/ntlm.c
index b9fdf6f237a..6b1249d2017 100644
--- a/dlls/secur32/tests/ntlm.c
+++ b/dlls/secur32/tests/ntlm.c
@@ -1165,7 +1165,7 @@ static void testSignSeal(void)
 
     trace("Testing with more than one buffer.\n");
 
-    crypt.cBuffers = sizeof(complex_data)/sizeof(complex_data[0]);
+    crypt.cBuffers = ARRAY_SIZE(complex_data);
     crypt.pBuffers = complex_data;
 
     complex_data[0].BufferType = SECBUFFER_DATA|SECBUFFER_READONLY_WITH_CHECKSUM;
@@ -1436,7 +1436,7 @@ static void test_cred_multiple_use(void)
             getSecError(ret));
 
     buffer_desc.ulVersion = SECBUFFER_VERSION;
-    buffer_desc.cBuffers = sizeof(buffers)/sizeof(buffers[0]);
+    buffer_desc.cBuffers = ARRAY_SIZE(buffers);
     buffer_desc.pBuffers = buffers;
 
     ret = pInitializeSecurityContextA(&cred, NULL, NULL, ISC_REQ_CONNECTION,
@@ -1487,7 +1487,7 @@ static void test_null_auth_data(void)
     buffers[0].pvBuffer = HeapAlloc(GetProcessHeap(), 0, buffers[0].cbBuffer);
 
     buffer_desc.ulVersion = SECBUFFER_VERSION;
-    buffer_desc.cBuffers = sizeof(buffers)/sizeof(buffers[0]);
+    buffer_desc.cBuffers = ARRAY_SIZE(buffers);
     buffer_desc.pBuffers = buffers;
 
     size = sizeof(user);
diff --git a/dlls/secur32/tests/secur32.c b/dlls/secur32/tests/secur32.c
index 40c272ada3a..2d2c2a69255 100644
--- a/dlls/secur32/tests/secur32.c
+++ b/dlls/secur32/tests/secur32.c
@@ -67,7 +67,7 @@ static void testGetComputerObjectNameA(void)
     BOOLEAN rc;
     UINT i;
 
-    for (i = 0; i < (sizeof(formats) / sizeof(formats[0])); i++) {
+    for (i = 0; i < ARRAY_SIZE(formats); i++) {
         size = 0;
         SetLastError(0xdeadbeef);
         rc = pGetComputerObjectNameA(formats[i], NULL, &size);
@@ -112,7 +112,7 @@ static void testGetComputerObjectNameW(void)
     BOOLEAN rc;
     UINT i;
 
-    for (i = 0; i < (sizeof(formats) / sizeof(formats[0])); i++) {
+    for (i = 0; i < ARRAY_SIZE(formats); i++) {
         size = 0;
         SetLastError(0xdeadbeef);
         rc = pGetComputerObjectNameW(formats[i], NULL, &size);
@@ -134,7 +134,7 @@ static void testGetComputerObjectNameW(void)
 
         if (GetLastError() != ERROR_INSUFFICIENT_BUFFER) continue;
 
-        size = sizeof(nameW)/sizeof(nameW[0]);
+        size = ARRAY_SIZE(nameW);
         SetLastError(0xdeadbeef);
         rc = pGetComputerObjectNameW(formats[i], nameW, &size);
         switch (formats[i])
@@ -158,7 +158,7 @@ static void testGetUserNameExA(void)
     BOOLEAN rc;
     UINT i;
 
-    for (i = 0; i < (sizeof(formats) / sizeof(formats[0])); i++) {
+    for (i = 0; i < ARRAY_SIZE(formats); i++) {
         size = sizeof(name);
         ZeroMemory(name, sizeof(name));
         rc = pGetUserNameExA(formats[i], name, &size);
@@ -205,7 +205,7 @@ static void testGetUserNameExW(void)
     BOOLEAN rc;
     UINT i;
 
-    for (i = 0; i < (sizeof(formats) / sizeof(formats[0])); i++) {
+    for (i = 0; i < ARRAY_SIZE(formats); i++) {
         size = sizeof(nameW);
         ZeroMemory(nameW, sizeof(nameW));
         rc = pGetUserNameExW(formats[i], nameW, &size);