diff --git a/src/navier-stokes.c b/src/navier-stokes.c
index af780a2..811d4b8 100644
--- a/src/navier-stokes.c
+++ b/src/navier-stokes.c
@@ -701,7 +701,7 @@ int ns_step_rkf45(
       }
     }
     // next delta to use in future steps
-    *next_delta=factor*(*delta)*pow(relative*tolerance/err,0.2);
+    *next_delta=(*delta)*pow(relative*tolerance/err,0.2);
   }
   // error too big: repeat with smaller step
   else{