✅ Must vs Have to · 🚫 Mustn’t vs Don’t have to

Obligation & rules (internal vs external), prohibition vs lack of necessity, and the correct forms for negatives, questions, past and future.

must + base verb (no “to”) mustn’t = prohibition have to / don’t have to = necessity / no necessity past: had to · future: will have to questions with do/does/did for have to “Must we…?” = formal/less common have got to (BrE) / gotta (informal)

🧩Form — MUST

HOW TO SAY IT

must + base verb: I must leave now. (not *must to leave)
mustn’t + base verb (negative): You mustn’t park here.
Must is a modal → no -s after he/she/it: He must go. (not *musts)
Questions (formal/rare): Must we call early?
No past/future forms: use had to / will have to for time reference.

✗ We don’t must arrive early. → ✓ We mustn’t arrive early.
✗ Yesterday I must take a taxi. → ✓ Yesterday I had to take a taxi.

⚙️Form — HAVE TO

HOW TO SAY IT

Affirmative: I have to wear a helmet. / He has to wear a helmet.
Negative (no obligation): I don’t have to wear a tie.
Questions: Do you have to leave now? / Did you have to wait long?
Past: I had to call a taxi. · Future: You will have to show ID.
✗ I ’ve to study. → ✓ I have to study.

BrE option

Have you got to leave? (= Do you have to…?) · Informal: I’ve got to run! (spoken gotta)

🧠Meaning — MUST vs HAVE TO

OBLIGATION

must = obligation from the speaker’s viewpoint (internal / personal):
“I must stop smoking.” · “You must be on time.”
have to = external rule/requirement:
“We have to wear helmets at work.” (company rule)

🚦Mustn’t vs Don’t have to

mustn’t = prohibition (it is necessary not to do it):
“You mustn’t use your phone in exams.”

don’t have to = no necessity (it’s optional):
“You don’t have to wait; I’ll call a taxi.”

✗ You mustn’t pay if you don’t want to. (means ‘it’s forbidden to pay’)
✓ You don’t have to pay if you don’t want to. (not necessary)

🗣️Naturalness

Everyday English prefers Do we have to…? over formal Must we…?
Use mustn’t for signs/rules: You mustn’t smoke here.
Use don’t have to to remove obligation: We don’t have to work on Friday.

🧪More examples

I must remember to email Sam. (speaker’s priority)
Students have to submit the form by noon. (rule)
She didn’t have to cook; we ordered pizza. (no need in the past)
You will have to renew your passport next year. (future necessity)
Visitors mustn’t feed the animals. (prohibition)

🚫Common mistakes

✗ He musts come. → ✓ He must come.
✗ We don’t must be late. → ✓ We mustn’t be late.
✗ You will must show ID. → ✓ You will have to show ID.
✗ Have you to leave now? → ✓ Do you have to leave now?
✗ I ’ve to go. → ✓ I have to go.

✅Quick checks

Internal/strong personal rule? → must
External rule/requirement? → have to
Prohibited? → mustn’t
Optional / not necessary? → don’t have to
Past / future obligation? → had to / will have to
Questions/negatives with have to? → use do/does/did

Recap: must (speaker-imposed) vs have to (externally imposed). mustn’t = forbidden; don’t have to = not necessary. Past/future only with have to → had to / will have to. Keep forms clean: no “to” after must, no “musts”, and use do/does/did with have to. 💡

✅ Must vs Have to · 🚫 Mustn’t vs Don’t have to

Have to, don’t have to, must, mustn’t

Choose the correct forms, don’t have to, mustn’t, to complete the sentences below.

Have to, don’t have to, must, mustn’t

Choose the most appropriate forms, have to, don’t have to, must, mustn’t, to complete the following sentences.

Have to, don’t have to, must, mustn’t

Read the interview with Maya about her job. Fill in the gaps with the verbs in brackets and the correct forms of have to (affirmative, negative, interrogative) in the present or past simple. Where natural, must is also accepted.