diff -r 6c2cd26095a5 -r 725da10db56c src/Utils.cpp
--- a/src/Utils.cpp	Tue May 17 21:19:31 2022 +0200
+++ b/src/Utils.cpp	Wed May 18 08:59:54 2022 +0200
@@ -241,6 +241,9 @@
 
 double Utils::calc_svg(double og, double fg)
 {
+    if (og == 0.0 || fg == 0.0)
+	return 0;
+
     double oe = sg_to_plato(og);
     double ae = sg_to_plato(fg);