diff --git a/fhem/FHEM/98_SVG.pm b/fhem/FHEM/98_SVG.pm
index 34f438e95..b570b5250 100755
--- a/fhem/FHEM/98_SVG.pm
+++ b/fhem/FHEM/98_SVG.pm
@@ -194,7 +194,7 @@ SVG_log10($)
 
   return 0.0000000001 if( $n <= 0 );
 
-  return log($n)/log(10);
+  return log(1+$n)/log(10);
 }
 
 
diff --git a/fhem/www/pgm2/svg.js b/fhem/www/pgm2/svg.js
index 6215cd132..76db3009a 100644
--- a/fhem/www/pgm2/svg.js
+++ b/fhem/www/pgm2/svg.js
@@ -259,7 +259,7 @@ sv_menu(evt, embed)
 
     if( par.log_scale ) {
       y *= par.log_scale;
-      y = Math.pow(10,y);
+      y = Math.pow(10,y) - 1;
     }
 
     y = y.toFixed(par.decimals);