diff --git a/src/loadFlash.cpp b/src/loadFlash.cpp
index de665d8..a07c156 100644
--- a/src/loadFlash.cpp
+++ b/src/loadFlash.cpp
@@ -45,8 +45,8 @@ SimuData *CosmoTool::loadFlashMulti(const char *fname, int id, int loadflags)
 
     h5_read_runtime_parameters(&file, &lbox, &npart, &hubble, &omegam, &omegalambda);
     data->TotalNumPart = data->NumPart = npart;
-    data->BoxSize = lbox/kpc2cm;
     data->Hubble = hubble/hubble2cm;
+    data->BoxSize = lbox/kpc2cm*data->Hubble;
     data->Omega_M = omegam;
     data->Omega_Lambda = omegalambda;