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Spanish · Verb · #508 most common

alterar

to alter
to disturb

Regular-ar ending

In the tables below, the stem is shown in black and the ending in purple.

1.

Presente

Habitual actions, general truths, and what's happening now.

yoaltero
alteras
él/ellaaltera
nosotrosalteramos
vosotrosalteráis
ellos/ellasalteran

Ella altera los documentos antes de enviarlos.

She alters the documents before sending them.

Nosotros alteramos la receta para hacerla más saludable.

We alter the recipe to make it healthier.

2.

Pretérito Indefinido

Completed actions at a specific point in the past.

yoalteré
alteraste
él/ellaalteró
nosotrosalteramos
vosotrosalterasteis
ellos/ellasalteraron

El ingeniero alteró el diseño del puente.

The engineer altered the design of the bridge.

Ayer, ellos alteraron el horario de la reunión.

Yesterday, they altered the schedule of the meeting.

3.

Imperfecto

Ongoing or repeated actions in the past, descriptions, and background context.

yoalteraba
alterabas
él/ellaalteraba
nosotrosalterábamos
vosotrosalterabais
ellos/ellasalteraban

Cuando era niño, siempre alteraba mis juguetes.

When I was a child, I always altered my toys.

Ella alteraba su voz para sonar diferente.

She altered her voice to sound different.

4.

Futuro Simple

Future actions, predictions, and speculation about the present.

yoalteraré
alterarás
él/ellaalterará
nosotrosalteraremos
vosotrosalteraréis
ellos/ellasalterarán

Mañana, él alterará los planes si es necesario.

Tomorrow, he will alter the plans if necessary.

Nosotros alteraremos el enfoque del proyecto.

We will alter the approach of the project.

5.

Condicional

Hypothetical situations, polite requests, and future-in-the-past.

yoalteraría
alterarías
él/ellaalteraría
nosotrosalteraríamos
vosotrosalteraríais
ellos/ellasalterarían

Yo alteraría el color de la pintura si pudiera.

I would alter the color of the paint if I could.

Ellos alterarían el sistema si hubiera problemas.

They would alter the system if there were problems.

6.

Subjuntivo Presente

Wishes, doubts, emotions, and subordinate clauses expressing uncertainty.

yoaltere
alteres
él/ellaaltere
nosotrosalteremos
vosotrosalteréis
ellos/ellasalteren

Es importante que ella altere su actitud.

It is important that she alters her attitude.

Espero que ellos alteren sus planes a tiempo.

I hope that they alter their plans on time.

7.

Subjuntivo Imperfecto

Past subjunctive contexts, hypothetical si-clauses, and polite suggestions.

yoalterara
alteraras
él/ellaalterara
nosotrosalteráramos
vosotrosalterarais
ellos/ellasalteraran

Si yo alterara los datos, podría obtener mejores resultados.

If I altered the data, I could get better results.

Si ellos alteraran el diseño, sería más atractivo.

If they altered the design, it would be more attractive.

Related verbs

Common questions
Is "alterar" regular or irregular in Spanish?
"alterar" is a regular -ar verb in Spanish. It follows the standard conjugation pattern for -ar verbs.
How do you conjugate "alterar" in the present tense?
In the Presente, "alterar" conjugates as: alteras, altero, alteran, and more. See the full table above.
What is the past tense of "alterar" in Spanish?
In the Pretérito Indefinido, "alterar" conjugates as: alteraste, alteré, alteraron, and more. See the full table above.
How common is "alterar" in Spanish?
"alterar" (to alter, to disturb) is one of the most commonly used verbs in Spanish.