diff --git a/source/convert_to_argb.cc b/source/convert_to_argb.cc
index 720cb0984..f3c4018d7 100644
--- a/source/convert_to_argb.cc
+++ b/source/convert_to_argb.cc
@@ -92,9 +92,11 @@ int ConvertToARGB(const uint8_t* sample,
   if (need_buf) {
     const uint64_t rotate_buffer_size =
         (uint64_t)crop_width * 4 * abs_crop_height;
+#if UINT64_MAX > SIZE_MAX
     if (rotate_buffer_size > SIZE_MAX) {
       return -1;  // Invalid size.
     }
+#endif
     rotate_buffer = (uint8_t*)malloc((size_t)rotate_buffer_size);
     if (!rotate_buffer) {
       return 1;  // Out of memory runtime error.
diff --git a/source/scale_argb.cc b/source/scale_argb.cc
index 4dc446d5e..8758d79c2 100644
--- a/source/scale_argb.cc
+++ b/source/scale_argb.cc
@@ -844,9 +844,11 @@ int YUVToARGBScaleClip(const uint8_t* src_y,
   }
   const int abs_src_height = (src_height < 0) ? -src_height : src_height;
   const uint64_t argb_buffer_size = (uint64_t)src_width * abs_src_height * 4;
+#if UINT64_MAX > SIZE_MAX
   if (argb_buffer_size > SIZE_MAX) {
     return -1;  // Invalid size.
   }
+#endif
   uint8_t* argb_buffer = (uint8_t*)malloc((size_t)argb_buffer_size);
   if (!argb_buffer) {
     return 1;  // Out of memory runtime error.
diff --git a/source/scale_rgb.cc b/source/scale_rgb.cc
index 6040b364e..0a2f2f6b9 100644
--- a/source/scale_rgb.cc
+++ b/source/scale_rgb.cc
@@ -53,9 +53,11 @@ int RGBScale(const uint8_t* src_rgb,
     return -1;  // Invalid size.
   }
   const uint64_t argb_size = src_argb_size + dst_argb_size;
+#if UINT64_MAX > SIZE_MAX
   if (argb_size > SIZE_MAX) {
     return -1;  // Invalid size.
   }
+#endif
   uint8_t* src_argb = (uint8_t*)malloc((size_t)argb_size);
   if (!src_argb) {
     return 1;  // Out of memory runtime error.