diff --git a/components/esm/defs.hpp b/components/esm/defs.hpp
index 1655766c79..f3e1ad640e 100644
--- a/components/esm/defs.hpp
+++ b/components/esm/defs.hpp
@@ -8,6 +8,7 @@
 
 #include <osg/Vec3f>
 
+#include "components/esm/fourcc.hpp"
 #include <components/esm4/common.hpp>
 
 namespace ESM
diff --git a/components/esm/format.hpp b/components/esm/format.hpp
index 6bb5e270c1..d33a241903 100644
--- a/components/esm/format.hpp
+++ b/components/esm/format.hpp
@@ -1,7 +1,7 @@
 #ifndef COMPONENT_ESM_FORMAT_H
 #define COMPONENT_ESM_FORMAT_H
 
-#include "defs.hpp"
+#include "components/esm/fourcc.hpp"
 
 #include <cstdint>
 #include <iosfwd>
diff --git a/components/esm/fourcc.hpp b/components/esm/fourcc.hpp
new file mode 100644
index 0000000000..cb0cd7a6a3
--- /dev/null
+++ b/components/esm/fourcc.hpp
@@ -0,0 +1,13 @@
+#ifndef OPENMW_COMPONENTS_ESM_FOURCC_H
+#define OPENMW_COMPONENTS_ESM_FOURCC_H
+
+namespace ESM
+{
+    inline constexpr unsigned int fourCC(const char (&name)[5])
+    {
+        return static_cast<unsigned char>(name[0]) | (static_cast<unsigned char>(name[1]) << 8)
+            | (static_cast<unsigned char>(name[2]) << 16) | (static_cast<unsigned char>(name[3]) << 24);
+    }
+}
+
+#endif // OPENMW_COMPONENTS_ESM_FOURCC_H
diff --git a/components/esm4/common.hpp b/components/esm4/common.hpp
index 5eae860a10..9d5b9e6bc6 100644
--- a/components/esm4/common.hpp
+++ b/components/esm4/common.hpp
@@ -30,18 +30,9 @@
 #include <cstdint>
 #include <string>
 
-#include "formid.hpp"
+#include "components/esm/fourcc.hpp"
 
-namespace ESM
-{
-    template <std::size_t len>
-    constexpr unsigned int fourCC(const char (&name)[len])
-    {
-        static_assert(len == 5, "Constant must be 4 characters long. (Plus null terminator)");
-        return static_cast<unsigned char>(name[0]) | (static_cast<unsigned char>(name[1]) << 8)
-            | (static_cast<unsigned char>(name[2]) << 16) | (static_cast<unsigned char>(name[3]) << 24);
-    }
-}
+#include "formid.hpp"
 
 namespace ESM4
 {