diff --git a/include/tex_len.h b/include/tex_len.h
new file mode 100644
index 0000000000..f6e54a82d1
--- /dev/null
+++ b/include/tex_len.h
@@ -0,0 +1,14 @@
+#ifndef TEX_LEN_H
+#define TEX_LEN_H
+
+/**
+ * Compute a length for an array holding a texture.
+ * `type` is the array's element type.
+ * `width`, `height` are the texture dimensions.
+ * `bpp` is the texture's pixel size, in bits per pixels.
+ * The calculation computes the size of the texture in bits `width * height * bpp`,
+ * then divides by 8 to get the size in bytes, then divides by the element type size.
+ */
+#define TEX_LEN(type, width, height, bpp) ((width) * (height) * (bpp) / 8 / sizeof(type))
+
+#endif
diff --git a/tools/assets/extract/extase_oot64/dlist_resources.py b/tools/assets/extract/extase_oot64/dlist_resources.py
index 63e8635a69..ad470c33aa 100644
--- a/tools/assets/extract/extase_oot64/dlist_resources.py
+++ b/tools/assets/extract/extase_oot64/dlist_resources.py
@@ -275,12 +275,19 @@ class TextureResource(Resource):
         self.width_name = f"{self.symbol_name}_WIDTH"
         self.height_name = f"{self.symbol_name}_HEIGHT"
 
+    def check_declare_length(self):
+        return (
+            hasattr(self, "HACK_IS_STATIC_ON") or EXPLICIT_DL_AND_TEX_SIZES
+        ) and not self.is_tlut()
+
     def get_c_declaration_base(self):
         if hasattr(self, "HACK_IS_STATIC_ON") and self.is_tlut():
             raise NotImplementedError
-        if hasattr(self, "HACK_IS_STATIC_ON") or EXPLICIT_DL_AND_TEX_SIZES:
-            if not self.is_tlut():
-                return f"{self.elem_type} {self.symbol_name}[{self.height_name} * {self.width_name} * {self.siz.bpp} / 8 / sizeof({self.elem_type})]"
+        if self.check_declare_length():
+            return (
+                f"{self.elem_type} {self.symbol_name}"
+                f"[TEX_LEN({self.elem_type}, {self.width_name}, {self.height_name}, {self.siz.bpp})]"
+            )
         return f"{self.elem_type} {self.symbol_name}[]"
 
     def get_c_reference(self, resource_offset: int):
@@ -518,7 +525,10 @@ class TextureResource(Resource):
         super().write_c_declaration(h)
 
     def get_h_includes(self):
-        return ("ultra64.h",)
+        return (
+            "ultra64.h",
+            *(("tex_len.h",) if self.check_declare_length() else ()),
+        )
 
     @reprlib.recursive_repr()
     def __repr__(self):