diff --git a/dsmon.sh b/dsmon.sh
index 131591a..727e101 100755
--- a/dsmon.sh
+++ b/dsmon.sh
@@ -167,7 +167,7 @@ CHECK(){
 
 			for DRIVE in "${DRIVES[@]}"; do
 
-				WARNING_LEVEL=$(expr 100 - ${host_limits_tmp[$DRIVE]})
+				WARNING_LEVEL=$(printf "%0.2f" $(jq -n 100-${host_limits_tmp[$DRIVE]}))
 				CRITICAL_LEVEL=$(printf "%0.2f" $(jq -n $WARNING_LEVEL-$WARNING_LEVEL/2))
 				
 				echo "warn=$WARNING_LEVEL - crit=$CRITICAL_LEVEL"