diff --git a/dlls/iphlpapi/iphlpapi_main.c b/dlls/iphlpapi/iphlpapi_main.c
index 55a6fa7b81b..e3898c2ca21 100644
--- a/dlls/iphlpapi/iphlpapi_main.c
+++ b/dlls/iphlpapi/iphlpapi_main.c
@@ -1579,8 +1579,10 @@ DWORD WINAPI GetTcpTable(PMIB_TCPTABLE pTcpTable, PDWORD pdwSize, BOOL bOrder)
     ret = ERROR_INVALID_PARAMETER;
   else {
     DWORD numEntries = getNumTcpEntries();
-    DWORD size = sizeof(MIB_TCPTABLE) + (numEntries - 1) * sizeof(MIB_TCPROW);
+    DWORD size = sizeof(MIB_TCPTABLE);
 
+    if (numEntries > 1)
+      size += (numEntries - 1) * sizeof(MIB_TCPROW);
     if (!pTcpTable || *pdwSize < size) {
       *pdwSize = size;
       ret = ERROR_INSUFFICIENT_BUFFER;
@@ -1588,8 +1590,9 @@ DWORD WINAPI GetTcpTable(PMIB_TCPTABLE pTcpTable, PDWORD pdwSize, BOOL bOrder)
     else {
       ret = getTcpTable(&pTcpTable, numEntries, 0, 0);
       if (!ret) {
-        size = sizeof(MIB_TCPTABLE) + (pTcpTable->dwNumEntries - 1) *
-         sizeof(MIB_TCPROW);
+        size = sizeof(MIB_TCPTABLE);
+        if (numEntries > 1)
+          size += (numEntries - 1) * sizeof(MIB_TCPROW);
         *pdwSize = size;
 
           if (bOrder)
diff --git a/dlls/iphlpapi/ipstats.c b/dlls/iphlpapi/ipstats.c
index 1ba57b194ed..6642804678f 100644
--- a/dlls/iphlpapi/ipstats.c
+++ b/dlls/iphlpapi/ipstats.c
@@ -1212,9 +1212,11 @@ DWORD getTcpTable(PMIB_TCPTABLE *ppTcpTable, DWORD maxEntries, HANDLE heap,
 
    if (!*ppTcpTable)
    {
-      *ppTcpTable = HeapAlloc (heap, flags,
-                               sizeof (MIB_TCPTABLE) +
-                               (numEntries - 1) * sizeof (MIB_TCPROW));
+      DWORD size = sizeof(MIB_TCPTABLE);
+
+      if (numEntries > 1)
+         size += (numEntries - 1) * sizeof (MIB_TCPROW);
+      *ppTcpTable = HeapAlloc (heap, flags, size);
       if (!*ppTcpTable)
       {
          ERR ("Out of memory!\n");