得了 / 用不着: enough!, no need to
【五24】【五25】固定短语 / phrases
Tone colorsā tone 1á tone 2ǎ tone 3à tone 4a neutral
得了 (déle) cuts the other person off: "enough, forget it". On its own or with 吧 (得了吧) it brushes aside what you have just heard, with disbelief; after a verb, V + 得了 offers the simplest way out, "just do it and be done with it". 用不着 ("no need to") already denies the need, so you say 用不着害怕 and never 用不着不…
Blunter than 不用 or 不必, 用不着 also pushes away someone's interference: 用不着你管 ("it's none of your business"). Depending on the tone it sounds irritated or just curt.
Both are spoken and used among friends, neighbours or equals; said to a superior or a stranger, 得了吧 would be rude. Do not mix up 得了 (déle) with the potential V得了 (liǎo) as in 吃得了 ("can eat it all"), nor with 算了 ("let it go", said mostly to oneself).
Examples
用不着客气，快请坐。
Yòngbuzháo kèqi, kuài qǐng zuò.No need to stand on ceremony, please sit down.
你们用不着等我，先吃吧。
Nǐmen yòngbuzháo děng wǒ, xiān chī ba.There's no need to wait for me, go ahead and eat.
得了吧，你上次也是这么说的，结果呢？
Déle ba, nǐ shàng cì yě shì zhème shuō de, jiéguǒ ne?Come off it! You said that last time too, and what came of it?
这是我自己家的事，用不着你管。
Zhè shì wǒ zìjǐ jiā de shì, yòngbuzháo nǐ guǎn.This is my own family's business, it's none of your concern.
打车太贵了，坐地铁去得了。
Dǎchē tài guì le, zuò dìtiě qù déle.A taxi costs too much, just take the subway and be done with it.
得了得了，别再说了，是我不对。
Déle déle, bié zài shuō le, shì wǒ bú duì.All right, all right, let's drop it, it's my fault.
Common mistakes
✗ 你用不着不去 → ✓ 你用不着去 (用不着 already says "no need", so it takes no 不).
✗ 老师，得了吧！ → ✓ 老师，您太客气了 (得了吧 is too curt for a superior; keep it for close people).
✗ 坐地铁得了去 → ✓ 坐地铁去得了 (得了 closes the sentence, after the verb and its complement).