diff --git a/package/base-files/files/bin/ipcalc.sh b/package/base-files/files/bin/ipcalc.sh
index 56854b41041..21f84bcaf2e 100755
--- a/package/base-files/files/bin/ipcalc.sh
+++ b/package/base-files/files/bin/ipcalc.sh
@@ -69,7 +69,7 @@ BEGIN {
 	if (start<limit) start=limit
 	if (start==ipaddr) start=ipaddr+1
 
-	end=start+ARGV[4]
+	end=start+ARGV[4]-1
 	limit=or(network,compl32(netmask))-1
 	if (end>limit) end=limit
 	if (end==ipaddr) end=ipaddr-1