Basarse Conjugation in Spanish

The Spanish verb basarse means to be based on, and it is a verb you will use again and again once you know it. Basarse means to be based on, and it is the reflexive partner of basar: a theory is based on experience, a decision is based on the facts, a film is based on a true story. It takes en for the foundation, as in basarse en hechos reales. Like every Spanish verb, basarse changes its ending for each person and tense, and this page gives you the complete picture: every tense, every person, the gerund and the past participle, all from the verified conjugation tables. For example, in the present tense you say me baso en los datos del informe, and in the preterite you say me basé en lo que dice el médico. Work through the tables below, read the notes for each tense, and then test yourself with the examples, the common mistakes and the quiz at the end of the page.

Quick facts

  • Infinitive: basarse
  • English: to be based on
  • Verb type: reflexive regular -ar verb
  • Ending: -ar
  • Gerund: basando
  • Past participle: basado
  • Auxiliary verb: haber (all perfect tenses are formed with haber + basado)
  • Reflexive pronouns: me, te, se, nos, os, se — one before every conjugated form, matching the person.

Pronunciation is not listed on this page: the verified tables do not include IPA for basarse, so no pronunciation is given rather than an invented one. Basarse is reflexive: me baso, te basas. It takes en: me baso en los datos, never me baso los datos.

Full conjugation tables

Every form below comes from the verified conjugation tables for basarse. The imperfect subjunctive is shown in its -ra forms; the -se forms use the same stem. For reflexive verbs, the pronoun column shows the reflexive pronoun that goes before each form.

Present indicative

Person Pronoun Form
yo me baso
tú te basas
él/ella/Ud. se basa
nosotros/as nos basamos
vosotros/as os basáis
ellos/ellas/Uds. se basan

Preterite

Person Pronoun Form
yo me basé
tú te basaste
él/ella/Ud. se basó
nosotros/as nos basamos
vosotros/as os basasteis
ellos/ellas/Uds. se basaron

Imperfect

Person Pronoun Form
yo me basaba
tú te basabas
él/ella/Ud. se basaba
nosotros/as nos basábamos
vosotros/as os basabais
ellos/ellas/Uds. se basaban

Future

Person Pronoun Form
yo me basaré
tú te basarás
él/ella/Ud. se basará
nosotros/as nos basaremos
vosotros/as os basaréis
ellos/ellas/Uds. se basarán

Conditional

Person Pronoun Form
yo me basaría
tú te basarías
él/ella/Ud. se basaría
nosotros/as nos basaríamos
vosotros/as os basaríais
ellos/ellas/Uds. se basarían

Present perfect

Person Pronoun Form
yo me he basado
tú te has basado
él/ella/Ud. se ha basado
nosotros/as nos hemos basado
vosotros/as os habéis basado
ellos/ellas/Uds. se han basado

Pluperfect

Person Pronoun Form
yo me había basado
tú te habías basado
él/ella/Ud. se había basado
nosotros/as nos habíamos basado
vosotros/as os habíais basado
ellos/ellas/Uds. se habían basado

Future perfect

Person Pronoun Form
yo me habré basado
tú te habrás basado
él/ella/Ud. se habrá basado
nosotros/as nos habremos basado
vosotros/as os habréis basado
ellos/ellas/Uds. se habrán basado

Conditional perfect

Person Pronoun Form
yo me habría basado
tú te habrías basado
él/ella/Ud. se habría basado
nosotros/as nos habríamos basado
vosotros/as os habríais basado
ellos/ellas/Uds. se habrían basado

Present subjunctive

Person Pronoun Form
yo me base
tú te bases
él/ella/Ud. se base
nosotros/as nos basemos
vosotros/as os baséis
ellos/ellas/Uds. se basen

Imperfect subjunctive (-ra)

Person Pronoun Form
yo me basara
tú te basaras
él/ella/Ud. se basara
nosotros/as nos basáramos
vosotros/as os basarais
ellos/ellas/Uds. se basaran

Imperative (affirmative)

Person Pronoun Form
tú te basa
él/ella/Ud. se base
nosotros/as nos basemos
vosotros/as os basad
ellos/ellas/Uds. se basen

Imperative (negative)

Person Pronoun Form
tú te bases
él/ella/Ud. se base
nosotros/as nos basemos
vosotros/as os baséis
ellos/ellas/Uds. se basen

Gerund and past participle

Form Spanish Use
Gerund basando with estar for the progressive: estoy basando (with the pronoun attached: basándose)
Past participle basado with haber for the perfect tenses: he basado

How to use each tense

Present indicative

Use the present for routines, general facts and what is happening right now. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the present looks like this in a real sentence: Me baso en los datos del informe. Learn the present forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Preterite

Use the preterite for finished actions with a clear end, often with ayer, el año pasado or anoche. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the preterite looks like this in a real sentence: Ayer, me basé en la experiencia de años. Learn the preterite forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Imperfect

Use the imperfect for background, habits and actions in progress in the past, often with de niño, antes or mientras. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the imperfect looks like this in a real sentence: De niño, me basaba en lo que dice el médico. Learn the imperfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Future

Use the future for plans, predictions and promises, often with mañana, el año que viene or pronto. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the future looks like this in a real sentence: Mañana, me basaré en hechos reales. Learn the future forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Conditional

Use the conditional for polite requests, hypotheticals and what would happen, often with si clauses. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the conditional looks like this in a real sentence: Me basaría en los datos del informe si pudiera. Learn the conditional forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Present perfect

Use the present perfect for recent actions and experiences, often with hoy, esta semana or ya. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the present perfect looks like this in a real sentence: Hoy, me he basado en la experiencia de años. Learn the present perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Pluperfect

Use the pluperfect when one past action happened before another past action. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the pluperfect looks like this in a real sentence: Me había basado en lo que dice el médico antes de salir. Learn the pluperfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Future perfect

Use the future perfect for something that will already be finished by a future time. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the future perfect looks like this in a real sentence: Para mañana, me habré basado en hechos reales. Learn the future perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Conditional perfect

Use the conditional perfect for what would have happened under different conditions. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the conditional perfect looks like this in a real sentence: Me habría basado en los datos del informe con más tiempo. Learn the conditional perfect forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Present subjunctive

Use the present subjunctive after expressions of wish, doubt, emotion and hope, such as espero que or quiero que. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the present subjunctive looks like this in a real sentence: Espero que él se base en la experiencia de años. Learn the present subjunctive forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Imperfect subjunctive (-ra)

Use the imperfect subjunctive after past wishes and in si clauses about the past, and note the -ra forms shown here; the -se forms use the same stem. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the imperfect subjunctive looks like this in a real sentence: Si él se basara en lo que dice el médico, todo cambiaría. Learn the imperfect subjunctive forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Imperative (affirmative)

Use the affirmative imperative for direct commands, instructions and invitations. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the affirmative imperative looks like this in a real sentence: Que se base en hechos reales. Learn the affirmative imperative forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Imperative (negative)

Use the negative imperative, always with no, to tell someone not to do something. For this verb the tense is regular, so the forms follow the standard endings for its verb class. For basarse, the negative imperative looks like this in a real sentence: No te bases en los datos del informe. Learn the negative imperative forms in the table above alongside this example, and notice how the ending, not the stem, usually carries the meaning of the tense.

Example sentences

Ten natural sentences with basarse, covering different tenses and persons. Each one uses a form from the tables above.

  1. Me baso en los datos del informe. — I rely on on the data in the report.
  2. Se basa en la experiencia de años. — He/she relies on on years of experience.
  3. Ayer, me basé en lo que dice el médico. — Yesterday, I relied on on what the doctor says.
  4. Antes, nosotros nos basábamos en hechos reales. — Before, we used to rely on on real facts.
  5. Mañana, tú te basarás en los datos del informe. — Tomorrow, you will rely on on the data in the report.
  6. Yo me basaría en la experiencia de años si tuviera más tiempo. — I would rely on on years of experience if I had more time.
  7. Él se ha basado en lo que dice el médico. — He has relied on on what the doctor says.
  8. Espero que él se base en hechos reales. — I hope he relies on on real facts.
  9. Yo ya me había basado en los datos del informe antes de salir. — I had already relied on on the data in the report before leaving.
  10. Ellos se basaban en la experiencia de años cuando eran jóvenes. — They used to rely on on years of experience when they were young.

Common mistakes

  1. Wrong: Yo baso en los datos del informe. — Right: Yo me baso en los datos del informe. — Basarse is reflexive, so the pronoun me is required: without it the verb means something else, or nothing at all.
  2. Wrong: Treating basarse and fundarse as identical in every context. — Right: Basarse means to be based on, while fundarse means to be founded on something. — They overlap, but each has uses the other does not: basarse fits sentences such as Me baso en los datos del informe, while fundarse belongs in a different sentence. Check the meaning you want before choosing.
  3. Wrong: Yo soy basado en la experiencia de años. — Right: Yo he basado en la experiencia de años. — Spanish perfect tenses use haber, not ser: he basado, has basado, ha basado. Ser plus the participle makes a passive, not a perfect tense.
  4. Wrong: De niño, yo basé en lo que dice el médico todos los días. — Right: De niño, yo basaba en lo que dice el médico todos los días. — For a repeated habit in the past, use the imperfect (basaba), not the preterite. The preterite (basé) is for one finished action.

Quiz: test yourself

Ten questions on basarse. Choose the right form, then check the answer key below.

  1. Complete the sentence: Yo ___ en los datos del informe. (present tense) A. me baso B. te basas C. se basa D. nos basamos

  2. Complete the sentence: Ayer, él ___ en la experiencia de años. (preterite) A. me basé B. te basaste C. se basaron D. se basó

  3. Complete the sentence: Antes, nosotros ___ en lo que dice el médico. (imperfect) A. te basabas B. se basaban C. nos basábamos D. me basaba

  4. Complete the sentence: Mañana, tú ___ en hechos reales. (future) A. nos basaremos B. te basarás C. me basaré D. se basará

  5. Complete the sentence: Yo ___ en los datos del informe si pudiera. (conditional) A. me basaría B. te basarías C. se basaría D. se basarían

  6. Complete the sentence: Espero que él ___ en la experiencia de años. (present subjunctive) A. me base B. te bases C. nos basemos D. se base

  7. Complete the sentence: Si yo ___ en lo que dice el médico, todo cambiaría. (imperfect subjunctive, -ra form) A. se basara B. nos basáramos C. me basara D. te basaras

  8. Complete the sentence: Nosotros ___ en hechos reales. (present perfect) A. se han basado B. nos hemos basado C. me he basado D. te has basado

  9. Complete the command: No ___ en los datos del informe. (negative imperative, tú) A. te bases B. se base C. nos basemos D. os baséis

  10. Which is the gerund of basarse, used with estar for the progressive? A. basado B. baso C. basé D. basando

Answer key

  1. me baso — The first-person present of basarse is me baso. The other options are the tú, él/ella and nosotros forms.
  2. se basó — The third-person preterite of basarse is se basó, the form for a single finished action in the past.
  3. nos basábamos — The nosotros imperfect of basarse is nos basábamos, used here for a repeated past habit.
  4. te basarás — The second-person future of basarse is te basarás.
  5. me basaría — The first-person conditional of basarse is me basaría, the form for what would happen.
  6. se base — After espero que, the subjunctive is required: the third-person present subjunctive of basarse is se base.
  7. me basara — The first-person imperfect subjunctive (-ra) of basarse is me basara.
  8. nos hemos basado — The nosotros present perfect of basarse is nos hemos basado: hemos + basado.
  9. te bases — The negative tú imperative uses the present subjunctive form with no before it: te bases.
  10. basando — The gerund of basarse is basando: estoy basando. The participle basado is used with haber instead.

Frequently asked questions

What does basarse mean in English?

Basarse means to be based on. It is used in everyday situations such as Me baso en los datos del informe. The exact English wording depends on the context, but the core meaning stays the same across the tenses.

Is basarse a reflexive verb?

Yes. Basarse is reflexive, so it always takes a reflexive pronoun that matches the person: me, te, se, nos, os or se. For example, Me baso en los datos del informe and él se basa en la experiencia de años. If you leave the pronoun out, the verb changes meaning or stops making sense.

What is the difference between basarse and fundarse?

Basarse means to be based on, while fundarse means to be founded on something. They are easy to confuse because they appear in similar situations, but they are not interchangeable: use basarse when you mean to be based on, as in Me baso en los datos del informe, and use fundarse for to be founded on something. When in doubt, check the object of the sentence — it usually shows which verb fits.

How do I say “I am based on” in the past?

It depends on the kind of past. For one finished action, use the preterite: yo me basé en la experiencia de años. For a repeated habit or background in the past, use the imperfect: yo me basaba en lo que dice el médico. For something that has just happened, use the present perfect: yo me he basado en la experiencia de años.

How do I practise basarse?

Start with the present tense table, then drill the preterite and the imperfect, since those two past tenses cause the most mistakes. Try the basarse examples and quiz page for more sentences, and use the Spanish Verb Quiz to test the forms under pressure.

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