diff --git a/cxplat/cxplat_test/cxplat_size_test.cpp b/cxplat/cxplat_test/cxplat_size_test.cpp
index a71b41d..4bcc069 100644
--- a/cxplat/cxplat_test/cxplat_size_test.cpp
+++ b/cxplat/cxplat_test/cxplat_size_test.cpp
@@ -6,31 +6,52 @@
 #else
 #include <catch2/catch.hpp>
 #endif
+#include <limits>
 #include "cxplat.h"
 
-TEST_CASE("cxplat_safe_size_t_multiply", "[size]")
+template <typename T>
+constexpr T
+cxplat_safe_integer_min_for_subtract_failure()
 {
-    size_t result;
-    REQUIRE(cxplat_safe_size_t_multiply(3, 5, &result) == CXPLAT_STATUS_SUCCESS);
-    REQUIRE(result == 15);
-
-    REQUIRE(cxplat_safe_size_t_multiply(SIZE_MAX, 2, &result) == CXPLAT_STATUS_ARITHMETIC_OVERFLOW);
+    return std::numeric_limits<T>::is_signed ? std::numeric_limits<T>::lowest() : static_cast<T>(0);
 }
 
-TEST_CASE("cxplat_safe_size_t_add", "[size]")
-{
-    size_t result;
-    REQUIRE(cxplat_safe_size_t_add(3, 5, &result) == CXPLAT_STATUS_SUCCESS);
-    REQUIRE(result == 8);
+#define CXPLAT_DEFINE_SAFE_INTEGER_TESTS(type, name, intsafe_name)                                                        \
+    TEST_CASE("cxplat_safe_" #name "_multiply", "[size]")                                                                 \
+    {                                                                                                                      \
+        type result;                                                                                                       \
+        REQUIRE(cxplat_safe_##name##_multiply(static_cast<type>(3), static_cast<type>(5), &result) ==                    \
+                CXPLAT_STATUS_SUCCESS);                                                                                    \
+        REQUIRE(result == static_cast<type>(15));                                                                          \
+                                                                                                                           \
+        REQUIRE(                                                                                                           \
+            cxplat_safe_##name##_multiply(std::numeric_limits<type>::max(), static_cast<type>(2), &result) ==            \
+            CXPLAT_STATUS_ARITHMETIC_OVERFLOW);                                                                            \
+    }                                                                                                                      \
+                                                                                                                           \
+    TEST_CASE("cxplat_safe_" #name "_add", "[size]")                                                                      \
+    {                                                                                                                      \
+        type result;                                                                                                       \
+        REQUIRE(cxplat_safe_##name##_add(static_cast<type>(3), static_cast<type>(5), &result) ==                         \
+                CXPLAT_STATUS_SUCCESS);                                                                                    \
+        REQUIRE(result == static_cast<type>(8));                                                                           \
+                                                                                                                           \
+        REQUIRE(cxplat_safe_##name##_add(std::numeric_limits<type>::max(), static_cast<type>(1), &result) ==             \
+                CXPLAT_STATUS_ARITHMETIC_OVERFLOW);                                                                        \
+    }                                                                                                                      \
+                                                                                                                           \
+    TEST_CASE("cxplat_safe_" #name "_subtract", "[size]")                                                                 \
+    {                                                                                                                      \
+        type result;                                                                                                       \
+        REQUIRE(cxplat_safe_##name##_subtract(static_cast<type>(5), static_cast<type>(3), &result) ==                    \
+                CXPLAT_STATUS_SUCCESS);                                                                                    \
+        REQUIRE(result == static_cast<type>(2));                                                                           \
+                                                                                                                           \
+        REQUIRE(cxplat_safe_##name##_subtract(                                                                             \
+                    cxplat_safe_integer_min_for_subtract_failure<type>(), static_cast<type>(1), &result) ==               \
+                CXPLAT_STATUS_ARITHMETIC_OVERFLOW);                                                                        \
+    }
 
-    REQUIRE(cxplat_safe_size_t_add(SIZE_MAX, 2, &result) == CXPLAT_STATUS_ARITHMETIC_OVERFLOW);
-}
-
-TEST_CASE("cxplat_safe_size_t_subtract", "[size]")
-{
-    size_t result;
-    REQUIRE(cxplat_safe_size_t_subtract(5, 3, &result) == CXPLAT_STATUS_SUCCESS);
-    REQUIRE(result == 2);
+CXPLAT_SAFE_INTEGER_TYPE_LIST(CXPLAT_DEFINE_SAFE_INTEGER_TESTS)
 
-    REQUIRE(cxplat_safe_size_t_subtract(3, 5, &result) == CXPLAT_STATUS_ARITHMETIC_OVERFLOW);
-}
\ No newline at end of file
+#undef CXPLAT_DEFINE_SAFE_INTEGER_TESTS
diff --git a/cxplat/inc/cxplat_size.h b/cxplat/inc/cxplat_size.h
index d407426..35ac44c 100644
--- a/cxplat/inc/cxplat_size.h
+++ b/cxplat/inc/cxplat_size.h
@@ -2,46 +2,51 @@
 // SPDX-License-Identifier: MIT
 #pragma once
 
+#include <stddef.h>
+#include <stdint.h>
 #include <stdbool.h>
 
 CXPLAT_EXTERN_C_BEGIN
 
 /**
- * @brief Multiplies one value of type size_t by another and check for
- *   overflow.
- * @param[in] multiplicand The value to be multiplied by multiplier.
- * @param[in] multiplier The value by which to multiply multiplicand.
- * @param[out] result A pointer to the result.
- * @retval CXPLAT_STATUS_SUCCESS The operation was successful.
- * @retval CXPLAT_STATUS_ARITHMETIC_OVERFLOW Multiplication overflowed.
+ * @brief Supported integer types for cxplat safe arithmetic helpers.
+ *
+ * The second parameter is the public function-name stem, and the third is the
+ * corresponding IntSafe/NtIntSafe primitive stem.
  */
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_multiply(
-    size_t multiplicand, size_t multiplier, _Out_ _Deref_out_range_(==, multiplicand* multiplier) size_t* result);
+#define CXPLAT_SAFE_INTEGER_TYPE_LIST(X) \
+    X(size_t, size_t, SizeT)             \
+    X(uint8_t, uint8_t, UInt8)           \
+    X(int8_t, int8_t, Int8)              \
+    X(uint16_t, uint16_t, UInt16)        \
+    X(int16_t, int16_t, Int16)           \
+    X(uint32_t, uint32_t, UInt32)        \
+    X(int32_t, int32_t, Int32)           \
+    X(uint64_t, uint64_t, UInt64)        \
+    X(int64_t, int64_t, Int64)
 
 /**
- * @brief Add one value of type size_t by another and check for
- *   overflow.
- * @param[in] augend The value to be added by addend.
- * @param[in] addend The value add to augend.
- * @param[out] result A pointer to the result.
- * @retval CXPLAT_STATUS_SUCCESS The operation was successful.
- * @retval CXPLAT_STATUS_ARITHMETIC_OVERFLOW Addition overflowed.
+ * @brief Safe checked arithmetic helpers for the supported integer types.
+ *
+ * Each listed type exposes:
+ * - cxplat_safe_<type>_multiply
+ * - cxplat_safe_<type>_add
+ * - cxplat_safe_<type>_subtract
+ *
+ * All helpers return CXPLAT_STATUS_SUCCESS on success and
+ * CXPLAT_STATUS_ARITHMETIC_OVERFLOW when the operation would overflow or
+ * underflow.
  */
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_add(size_t augend, size_t addend, _Out_ _Deref_out_range_(==, augend + addend) size_t* result);
+#define CXPLAT_DECLARE_SAFE_INTEGER_OPERATIONS(type, name, intsafe_name)                                                  \
+    _Must_inspect_result_ cxplat_status_t cxplat_safe_##name##_multiply(                                                  \
+        type multiplicand, type multiplier, _Out_ _Deref_out_range_(==, multiplicand * multiplier) type * result);       \
+    _Must_inspect_result_ cxplat_status_t                                                                                  \
+    cxplat_safe_##name##_add(type augend, type addend, _Out_ _Deref_out_range_(==, augend + addend) type * result);      \
+    _Must_inspect_result_ cxplat_status_t cxplat_safe_##name##_subtract(                                                  \
+        type minuend, type subtrahend, _Out_ _Deref_out_range_(==, minuend - subtrahend) type * result);
 
-/**
- * @brief Subtract one value of type size_t from another and check for
- *   overflow or underflow.
- * @param[in] minuend The value from which subtrahend is subtracted.
- * @param[in] subtrahend The value subtract from minuend.
- * @param[out] result A pointer to the result.
- * @retval CXPLAT_STATUS_SUCCESS The operation was successful.
- * @retval CXPLAT_STATUS_ARITHMETIC_OVERFLOW Addition overflowed or underflowed.
- */
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_subtract(
-    size_t minuend, size_t subtrahend, _Out_ _Deref_out_range_(==, minuend - subtrahend) size_t* result);
+CXPLAT_SAFE_INTEGER_TYPE_LIST(CXPLAT_DECLARE_SAFE_INTEGER_OPERATIONS)
+
+#undef CXPLAT_DECLARE_SAFE_INTEGER_OPERATIONS
 
 CXPLAT_EXTERN_C_END
diff --git a/cxplat/src/cxplat_winkernel/CMakeLists.txt b/cxplat/src/cxplat_winkernel/CMakeLists.txt
index 38f019f..0fb2909 100644
--- a/cxplat/src/cxplat_winkernel/CMakeLists.txt
+++ b/cxplat/src/cxplat_winkernel/CMakeLists.txt
@@ -14,6 +14,7 @@ add_library(cxplat_winkernel STATIC
   module_winkernel.c
   processor_winkernel.c
   rundown_winkernel.c
+  size_winkernel.cpp
   time_winkernel.c
   workitem_winkernel.c
 )
diff --git a/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj b/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj
index f9f7558..e3436e6 100644
--- a/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj
+++ b/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj
@@ -12,7 +12,7 @@
     <ClCompile Include="module_winkernel.c" />
     <ClCompile Include="processor_winkernel.c" />
     <ClCompile Include="rundown_winkernel.c" />
-    <ClCompile Include="size_winkernel.c" />
+    <ClCompile Include="size_winkernel.cpp" />
     <ClCompile Include="time_winkernel.c" />
     <ClCompile Include="workitem_winkernel.c" />
   </ItemGroup>
@@ -117,4 +117,4 @@
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj.filters b/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj.filters
index d251f3c..4308da7 100644
--- a/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj.filters
+++ b/cxplat/src/cxplat_winkernel/cxplat_winkernel.vcxproj.filters
@@ -21,7 +21,7 @@
     <ClCompile Include="memory_winkernel.c">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="size_winkernel.c">
+    <ClCompile Include="size_winkernel.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="rundown_winkernel.c">
@@ -78,4 +78,4 @@
       <Filter>Header Files</Filter>
     </ClInclude>
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/cxplat/src/cxplat_winkernel/size_winkernel.c b/cxplat/src/cxplat_winkernel/size_winkernel.c
deleted file mode 100644
index c0f67a8..0000000
--- a/cxplat/src/cxplat_winkernel/size_winkernel.c
+++ /dev/null
@@ -1,27 +0,0 @@
-// Copyright (c) Microsoft Corporation
-// SPDX-License-Identifier: MIT
-#include "cxplat.h"
-#include <ntintsafe.h>
-
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_multiply(
-    size_t multiplicand, size_t multiplier, _Out_ _Deref_out_range_(==, multiplicand* multiplier) size_t* result)
-{
-    return RtlSizeTMult(multiplicand, multiplier, result) == STATUS_SUCCESS ? CXPLAT_STATUS_SUCCESS
-                                                                            : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;
-}
-
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_add(size_t augend, size_t addend, _Out_ _Deref_out_range_(==, augend + addend) size_t* result)
-{
-    return RtlSizeTAdd(augend, addend, result) == STATUS_SUCCESS ? CXPLAT_STATUS_SUCCESS
-                                                                 : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;
-}
-
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_subtract(
-    size_t minuend, size_t subtrahend, _Out_ _Deref_out_range_(==, minuend - subtrahend) size_t* result)
-{
-    return RtlSizeTSub(minuend, subtrahend, result) == STATUS_SUCCESS ? CXPLAT_STATUS_SUCCESS
-                                                                      : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;
-}
\ No newline at end of file
diff --git a/cxplat/src/cxplat_winkernel/size_winkernel.cpp b/cxplat/src/cxplat_winkernel/size_winkernel.cpp
new file mode 100644
index 0000000..f862999
--- /dev/null
+++ b/cxplat/src/cxplat_winkernel/size_winkernel.cpp
@@ -0,0 +1,40 @@
+// Copyright (c) Microsoft Corporation
+// SPDX-License-Identifier: MIT
+#include "cxplat.h"
+
+#define ENABLE_INTSAFE_SIGNED_FUNCTIONS
+#include <ntintsafe.h>
+
+#define CXPLAT_NTINTSAFE_OPERATION(stem, operation) CXPLAT_NTINTSAFE_OPERATION_(stem, operation)
+#define CXPLAT_NTINTSAFE_OPERATION_(stem, operation) Rtl##stem##operation
+
+#define CXPLAT_DEFINE_SAFE_INTEGER_OPERATIONS(type, name, intsafe_name)                                                   \
+    _Must_inspect_result_ cxplat_status_t cxplat_safe_##name##_multiply(                                                  \
+        type multiplicand, type multiplier, _Out_ _Deref_out_range_(==, multiplicand * multiplier) type * result)        \
+    {                                                                                                                      \
+        return CXPLAT_NTINTSAFE_OPERATION(intsafe_name, Mult)(multiplicand, multiplier, result) == STATUS_SUCCESS         \
+                   ? CXPLAT_STATUS_SUCCESS                                                                                \
+                   : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;                                                                   \
+    }                                                                                                                      \
+                                                                                                                           \
+    _Must_inspect_result_ cxplat_status_t                                                                                  \
+    cxplat_safe_##name##_add(type augend, type addend, _Out_ _Deref_out_range_(==, augend + addend) type * result)       \
+    {                                                                                                                      \
+        return CXPLAT_NTINTSAFE_OPERATION(intsafe_name, Add)(augend, addend, result) == STATUS_SUCCESS                    \
+                   ? CXPLAT_STATUS_SUCCESS                                                                                \
+                   : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;                                                                   \
+    }                                                                                                                      \
+                                                                                                                           \
+    _Must_inspect_result_ cxplat_status_t cxplat_safe_##name##_subtract(                                                  \
+        type minuend, type subtrahend, _Out_ _Deref_out_range_(==, minuend - subtrahend) type * result)                  \
+    {                                                                                                                      \
+        return CXPLAT_NTINTSAFE_OPERATION(intsafe_name, Sub)(minuend, subtrahend, result) == STATUS_SUCCESS               \
+                   ? CXPLAT_STATUS_SUCCESS                                                                                \
+                   : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;                                                                   \
+    }
+
+CXPLAT_SAFE_INTEGER_TYPE_LIST(CXPLAT_DEFINE_SAFE_INTEGER_OPERATIONS)
+
+#undef CXPLAT_DEFINE_SAFE_INTEGER_OPERATIONS
+#undef CXPLAT_NTINTSAFE_OPERATION_
+#undef CXPLAT_NTINTSAFE_OPERATION
diff --git a/cxplat/src/cxplat_winuser/CMakeLists.txt b/cxplat/src/cxplat_winuser/CMakeLists.txt
index fc20ab5..749f2f7 100644
--- a/cxplat/src/cxplat_winuser/CMakeLists.txt
+++ b/cxplat/src/cxplat_winuser/CMakeLists.txt
@@ -19,7 +19,7 @@ add_library(cxplat_winuser STATIC
   module_winuser.cpp
   processor_winuser.cpp
   rundown_winuser.cpp
-  size_winuser.c
+  size_winuser.cpp
   workitem_winuser.cpp
   symbol_decoder.h
   time_winuser.cpp
diff --git a/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj b/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj
index ae5f872..0bb61ba 100644
--- a/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj
+++ b/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj
@@ -120,11 +120,11 @@
     <ClCompile Include="module_winuser.cpp" />
     <ClCompile Include="processor_winuser.cpp" />
     <ClCompile Include="rundown_winuser.cpp" />
-    <ClCompile Include="size_winuser.c" />
+    <ClCompile Include="size_winuser.cpp" />
     <ClCompile Include="time_winuser.cpp" />
     <ClCompile Include="workitem_winuser.cpp" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj.filters b/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj.filters
index 9854f89..ced706d 100644
--- a/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj.filters
+++ b/cxplat/src/cxplat_winuser/cxplat_winuser.vcxproj.filters
@@ -80,7 +80,7 @@
     <ClCompile Include="..\memory.c">
       <Filter>Source Files</Filter>
     </ClCompile>
-    <ClCompile Include="size_winuser.c">
+    <ClCompile Include="size_winuser.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
     <ClCompile Include="rundown_winuser.cpp">
@@ -99,4 +99,4 @@
       <Filter>Source Files</Filter>
     </ClCompile>
   </ItemGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/cxplat/src/cxplat_winuser/size_winuser.c b/cxplat/src/cxplat_winuser/size_winuser.c
deleted file mode 100644
index 7f17876..0000000
--- a/cxplat/src/cxplat_winuser/size_winuser.c
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright (c) Microsoft Corporation
-// SPDX-License-Identifier: MIT
-#include "cxplat.h"
-#include <intsafe.h>
-
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_multiply(
-    size_t multiplicand, size_t multiplier, _Out_ _Deref_out_range_(==, multiplicand* multiplier) size_t* result)
-{
-    return SUCCEEDED(SizeTMult(multiplicand, multiplier, result)) ? CXPLAT_STATUS_SUCCESS
-                                                                  : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;
-}
-
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_add(size_t augend, size_t addend, _Out_ _Deref_out_range_(==, augend + addend) size_t* result)
-{
-    return SUCCEEDED(SizeTAdd(augend, addend, result)) ? CXPLAT_STATUS_SUCCESS : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;
-}
-
-_Must_inspect_result_ cxplat_status_t
-cxplat_safe_size_t_subtract(
-    size_t minuend, size_t subtrahend, _Out_ _Deref_out_range_(==, minuend - subtrahend) size_t* result)
-{
-    return SUCCEEDED(SizeTSub(minuend, subtrahend, result)) ? CXPLAT_STATUS_SUCCESS : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;
-}
\ No newline at end of file
diff --git a/cxplat/src/cxplat_winuser/size_winuser.cpp b/cxplat/src/cxplat_winuser/size_winuser.cpp
new file mode 100644
index 0000000..c0c23f2
--- /dev/null
+++ b/cxplat/src/cxplat_winuser/size_winuser.cpp
@@ -0,0 +1,40 @@
+// Copyright (c) Microsoft Corporation
+// SPDX-License-Identifier: MIT
+#include "cxplat.h"
+
+#define ENABLE_INTSAFE_SIGNED_FUNCTIONS
+#include <intsafe.h>
+
+#define CXPLAT_INTSAFE_OPERATION(stem, operation) CXPLAT_INTSAFE_OPERATION_(stem, operation)
+#define CXPLAT_INTSAFE_OPERATION_(stem, operation) stem##operation
+
+#define CXPLAT_DEFINE_SAFE_INTEGER_OPERATIONS(type, name, intsafe_name)                                                   \
+    _Must_inspect_result_ cxplat_status_t cxplat_safe_##name##_multiply(                                                  \
+        type multiplicand, type multiplier, _Out_ _Deref_out_range_(==, multiplicand * multiplier) type * result)        \
+    {                                                                                                                      \
+        return SUCCEEDED(CXPLAT_INTSAFE_OPERATION(intsafe_name, Mult)(multiplicand, multiplier, result))                  \
+                   ? CXPLAT_STATUS_SUCCESS                                                                                \
+                   : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;                                                                   \
+    }                                                                                                                      \
+                                                                                                                           \
+    _Must_inspect_result_ cxplat_status_t                                                                                  \
+    cxplat_safe_##name##_add(type augend, type addend, _Out_ _Deref_out_range_(==, augend + addend) type * result)       \
+    {                                                                                                                      \
+        return SUCCEEDED(CXPLAT_INTSAFE_OPERATION(intsafe_name, Add)(augend, addend, result))                             \
+                   ? CXPLAT_STATUS_SUCCESS                                                                                \
+                   : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;                                                                   \
+    }                                                                                                                      \
+                                                                                                                           \
+    _Must_inspect_result_ cxplat_status_t cxplat_safe_##name##_subtract(                                                  \
+        type minuend, type subtrahend, _Out_ _Deref_out_range_(==, minuend - subtrahend) type * result)                  \
+    {                                                                                                                      \
+        return SUCCEEDED(CXPLAT_INTSAFE_OPERATION(intsafe_name, Sub)(minuend, subtrahend, result))                        \
+                   ? CXPLAT_STATUS_SUCCESS                                                                                \
+                   : CXPLAT_STATUS_ARITHMETIC_OVERFLOW;                                                                   \
+    }
+
+CXPLAT_SAFE_INTEGER_TYPE_LIST(CXPLAT_DEFINE_SAFE_INTEGER_OPERATIONS)
+
+#undef CXPLAT_DEFINE_SAFE_INTEGER_OPERATIONS
+#undef CXPLAT_INTSAFE_OPERATION_
+#undef CXPLAT_INTSAFE_OPERATION