diff --git a/RecoTracker/MkFitCore/src/HitStructures.cc b/RecoTracker/MkFitCore/src/HitStructures.cc
index 258bf295d72f6..91d9cebdeb60a 100644
--- a/RecoTracker/MkFitCore/src/HitStructures.cc
+++ b/RecoTracker/MkFitCore/src/HitStructures.cc
@@ -170,13 +170,14 @@ namespace mkfit {
     m_binnor.register_entry_safe(phi, q);
 
     if (Config::usePhiQArrays) {
-      const float sqrt3 = std::sqrt(3);
+      // Factor to get from hit sigma to half-length in q direction.
+      const float hl_fac = is_pixel() ? 3.0f : std::sqrt(3.0f);
       float half_length, qbar;
       if (m_is_barrel) {
-        half_length = sqrt3 * std::sqrt(h.ezz());
+        half_length = hl_fac * std::sqrt(h.ezz());
         qbar = h.r();
       } else {
-        half_length = sqrt3 * std::sqrt(h.exx() + h.eyy());
+        half_length = hl_fac * std::sqrt(h.exx() + h.eyy());
         qbar = h.z();
       }
       m_hit_infos.emplace_back(HitInfo({phi, q, half_length, qbar}));