Weak Responses to 1 NT

There's No Minimum HCP Range. Generally, to bid at all, responder needs a hand which can stand a contract of Two No Trump.

Exceptions are when he is making a weak transfer to a minor or will pass a forced Jacoby Transfer response by opener. If responder is bidding a Jacoby Transfer, he may intend to pass the response, sure in the knowledge opener will bid as directed.

When responder bids 2§ Stayman, he can rebid two or three Notrump if opener shows no four card major, or he can transfer to 3§ or 3¨ with a weak minor-suited hand.

Sometimes, he can pass a four card Major rebid by opener with three of the major suit.

N	S
1N	2§ Stayman	South should pass 2ª or 2© or bid 2© over 2¨ (inviting a pass or 2ª's) with this hand - -it'll probably be better than Pass at 1NT.
North	South
ª Kxx	ª Jxxx
© Qxx	© KJxx
¨ Axxx	¨ -
§ AKx	§ xxxxx