diff --git a/calc_grad_perc_dev.cc b/calc_grad_perc_dev.cc
index 86e13fa8eabf5bac81513efc5852a21d80a17cfd..5cd738bce8fda58af3f33d9447a31dec5780532b 100644
--- a/calc_grad_perc_dev.cc
+++ b/calc_grad_perc_dev.cc
@@ -64,27 +64,27 @@ int do_work(int argc, char* argv[])
   xpd.addvolume((tmp[0]+tmp[1])*0.5f);
   tmp=lrzgrad(fw[0],mask);
   xpd.addvolume((tmp[0]+tmp[1])*0.5f);
-  xpd[0]/=fw.xdim();
-  xpd[1]/=fw.ydim();
-  xpd[2]/=fw.zdim();
+  xpd[0]*=100.0/fw.xdim();
+  xpd[1]*=100.0/fw.ydim();
+  xpd[2]*=100.0/fw.zdim();
   tmp=lrxgrad(fw[1],mask);
   ypd.addvolume((tmp[0]+tmp[1])*0.5f);
   tmp=lrygrad(fw[1],mask);
   ypd.addvolume((tmp[0]+tmp[1])*0.5f);
   tmp=lrzgrad(fw[1],mask);
   ypd.addvolume((tmp[0]+tmp[1])*0.5f);
-  ypd[0]/=fw.xdim();
-  ypd[1]/=fw.ydim();
-  ypd[2]/=fw.zdim();
+  ypd[0]*=100.0/fw.xdim();
+  ypd[1]*=100.0/fw.ydim();
+  ypd[2]*=100.0/fw.zdim();
   tmp=lrxgrad(fw[2],mask);
   zpd.addvolume((tmp[0]+tmp[1])*0.5f);
   tmp=lrygrad(fw[2],mask);
   zpd.addvolume((tmp[0]+tmp[1])*0.5f);
   tmp=lrzgrad(fw[2],mask);
   zpd.addvolume((tmp[0]+tmp[1])*0.5f);
-  zpd[0]/=fw.xdim();
-  zpd[1]/=fw.ydim();
-  zpd[2]/=fw.zdim();
+  zpd[0]*=100.0/fw.xdim();
+  zpd[1]*=100.0/fw.ydim();
+  zpd[2]*=100.0/fw.zdim();
   string bname=fslbasename(outname.value());
   save_volume4D(xpd,bname+"_x");
   save_volume4D(ypd,bname+"_y");