diff --git a/Kernel/KBufferBuilder.h b/Kernel/KBufferBuilder.h
index d96eed409d..426b7c8d9b 100644
--- a/Kernel/KBufferBuilder.h
+++ b/Kernel/KBufferBuilder.h
@@ -52,6 +52,11 @@ public:
         return m_buffer->bytes();
     }
 
+    size_t length() const
+    {
+        return m_size;
+    }
+
 private:
     explicit KBufferBuilder(NonnullOwnPtr<KBuffer>);