diff --git a/calcDelta.py b/calcDelta.py
index 684c182..7442092 100644
--- a/calcDelta.py
+++ b/calcDelta.py
@@ -182,7 +182,7 @@ def calcDelta(data_f, data_w, eloverlap, useasymm):
         b0f[i] = data_f['B0'][searchnr] * 10.**9. / 1.602176565e-19 / 10.**30.
         b1f[i] = data_f['BP'][searchnr]
 
-    vref = 30.
+    vref = 30. * 0.5291772105 ** 3.
     bref = 100. * 10.**9. / 1.602176565e-19 / 10.**30.
 
     if useasymm: