diff --git a/src/bmtf_orbit_processor.h b/src/bmtf_orbit_processor.h
index 87150630b0a02bd320c6da941ce84bd2cda52f83..897d10c289dbd20b96f3056ef923d678abc41f76 100644
--- a/src/bmtf_orbit_processor.h
+++ b/src/bmtf_orbit_processor.h
@@ -16,7 +16,8 @@ class BmtfOrbitProcessor : public OrbitProcessor {
   }
 
   inline uint32_t GetOrbitSizeInBytes(const FillOrbitMetadata &meta) const override {
-    return GetPacketSize() * meta.filled_bxs;
+    // Each BX requires 3 words (12 bytes); each stub takes 8 bytes
+    return 12 * meta.filled_bxs + 8 * meta.counts;
   }
 };