diff --git a/src/main/java/net/kuraczyk/banhammer/cmds/Ban.java b/src/main/java/net/kuraczyk/banhammer/cmds/Ban.java
index 227ecbe..b3a85e2 100644
--- a/src/main/java/net/kuraczyk/banhammer/cmds/Ban.java
+++ b/src/main/java/net/kuraczyk/banhammer/cmds/Ban.java
@@ -45,6 +45,12 @@ public class Ban implements CommandExecutor {
             if(args.length>=2) scope=args[1];
             if(args.length>=3) {
                 duration=args[2];
+                String regex = "^\\d+:(s|m|h|d)$";
+                String regexOnlyNum = "^\\d+$";
+                if(!(duration.matches(regex) || duration.matches(regexOnlyNum))) {
+                    p.sendMessage(TextUtils.colorString(plugin.translations.getString("command.ban.durationFormatError")));
+                    return false;
+                }
                 char type = plugin.config.getString("defaultDurationType").charAt(0);
                 Integer time=0;
                 boolean chk = false;