Modal Verbs

What is a modal verb? (English)

A modal verb is a helper verb that expresses possibility, ability, obligation, or intention. It pairs with a main verb (in its base form) to modify the meaning.

Modal	Meaning	Example
can	ability	I can run fast.
could	past ability / possibility	She could help us.
must	strong obligation	You must leave now.
should	recommendation	He should rest.
will	future intention	They will arrive soon.
would	conditional	I would help if I could.
may	permission / possibility	You may go.
might	weaker possibility	It might rain.

Key properties of English modals

• Never conjugated: I can, she can, they can — no -s added
• Always followed by the base infinitive (no to): I must go, not I must to go

Examples

Modal	Sentence
can	I can finish this by Friday.
must	You must back up your work.
should	She should call back.
will	He will review the PR.
would	We would go if we had time.
may	You may use the conference room.
might	It might cause a bug.
could	They could ship next week.
have to	I have to submit the report.
need to	She needs to restart the server.

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How Spanish handles modals differently

Spanish does not have a separate class of modal verbs — it uses regular verbs that happen to carry modal meaning. These verbs are conjugated normally and are followed by an infinitive.

Structure: conjugated modal verb + infinitive

Quiero comer. = I want to eat. (quiero = I want, comer = to eat)

This is similar to “I want to eat” in English — but in Spanish, this pattern is how all modal-like expressions work.

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The 4 core Spanish modal verbs

poder — can / to be able to

Subject	Conjugation
yo	puedo
tú	puedes
él/ella/usted	puede
nosotros	podemos
vosotros	podéis
ellos/ustedes	pueden

Stem-changing: o → ue (except nosotros/vosotros)

Spanish	English
Yo puedo ayudarte.	I can help you.
¿Podéis venir mañana?	Can you all come tomorrow?
Ella puede correr rápido.	She can run fast.
Nosotros podemos terminar hoy.	We can finish today.
Ellos no pueden esperar.	They can’t wait.
¿Puede usted firmar aquí?	Can you sign here? (formal)
Yo no puedo hacerlo solo.	I can’t do it alone.
¿Podemos salir ya?	Can we leave now?
Él puede hablar tres idiomas.	He can speak three languages.
Tú puedes lograrlo.	You can achieve it.

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querer — to want

Subject	Conjugation
yo	quiero
tú	quieres
él/ella/usted	quiere
nosotros	queremos
vosotros	queréis
ellos/ustedes	quieren

Stem-changing: e → ie (except nosotros/vosotros)

Spanish	English
Yo quiero aprender español.	I want to learn Spanish.
¿Queréis comer algo?	Do you all want to eat something?
Ella quiere descansar.	She wants to rest.
Nosotros queremos salir.	We want to go out.
Ellos quieren un café.	They want a coffee.
¿Quiere usted algo más?	Would you like anything else? (formal)
No quiero llegar tarde.	I don’t want to arrive late.
¿Qué quieres hacer?	What do you want to do?
Él quiere comprar una casa.	He wants to buy a house.
Tú quieres hablar con ella.	You want to talk to her.

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deber — must / should / to owe

Subject	Conjugation
yo	debo
tú	debes
él/ella/usted	debe
nosotros	debemos
vosotros	debéis
ellos/ustedes	deben

Regular -er verb.

Spanish	English
Yo debo estudiar más.	I must study more.
Tú debes descansar.	You should rest.
Ella debe llamar al doctor.	She should call the doctor.
Vosotros debéis prestar atención.	You all must pay attention.
Ellos deben respetar las reglas.	They must respect the rules.
Usted debe firmar el documento.	You must sign the document.
Yo debo terminar esto hoy.	I have to finish this today.
¿Debo preocuparme?	Should I worry?
Él debe saber la verdad.	He should know the truth.
Debemos hablar de esto.	We need to talk about this.

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tener que — to have to (obligation)

tener que is a phrase, not a single verb. Conjugate tener, keep que, then add the infinitive.

Subject	Conjugation
yo	tengo que
tú	tienes que
él/ella/usted	tiene que
nosotros	tenemos que
vosotros	tenéis que
ellos/ustedes	tienen que

Spanish	English
Yo tengo que irme.	I have to leave.
Tú tienes que estudiar.	You have to study.
Ella tiene que trabajar hoy.	She has to work today.
Vosotros tenéis que decidir.	You all have to decide.
Ellos tienen que esperar.	They have to wait.
Usted tiene que firmar aquí.	You have to sign here.
¿Tienes que salir ahora?	Do you have to leave now?
Yo tengo que llamar a mi madre.	I have to call my mother.
Él tiene que comer.	He has to eat.
Tenemos que hablar.	We need to talk.

tener que names a specific person’s obligation. For the impersonal version — a rule for anyone/no one in particular — see tener for the full tener que vs. hay que comparison.

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Strength of obligation: comparison

Spanish	Approximate English	Strength
poder + inf.	can	ability
querer + inf.	want to	desire
deber + inf.	should / must	moral obligation
tener que + inf.	have to	practical obligation

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Common mistakes

• ❌ Using modal + conjugated verb: Puedo hablo → ✅ Puedo hablar — always infinitive after modal
• ❌ Forgetting stem changes: Yo poder → ✅ Yo puedo (o→ue)
• ❌ Saying debo de when expressing obligation → ✅ debo alone means “must”; deber de = probability
• ❌ Separating tener que: Tengo estudiar → ✅ Tengo que estudiar

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Summary

• Spanish modals are regular verbs conjugated by subject + followed by an infinitive
• The 4 core modals: poder (can), querer (want to), deber (should/must), tener que (have to)
• Structure: [conjugated modal] + [infinitive]
• Strength: poder < querer < deber < tener que

See also: Present Tense — conjugation patterns these verbs follow.
See also: Verb Types — -ar/-er/-ir classification.