diff --git a/include/openmc/particle.h b/include/openmc/particle.h
index 4b72e96c0..bef2b1984 100644
--- a/include/openmc/particle.h
+++ b/include/openmc/particle.h
@@ -186,7 +186,7 @@ public:
     Position r;
     Direction u;
     double E;
-	double wgt;
+    double wgt;
   };