Decaer Conjugation in Spanish
The Spanish verb decaer means to decline, to weaken, and it is a verb you will use again and again once you know it. Decaer means to decline or to weaken, and it is used for health declining, interest fading and an empire falling. It follows the pattern of caer, with the present decaigo and the preterite decaí, and it is the verb for a slow, steady fall. Like every Spanish verb, decaer 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 decaigo con la edad y la enfermedad, and in the preterite you say decaí el interés por el proyecto. 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: decaer
- English: to decline, to weaken
- Verb type: irregular verb
- Ending: -er
- Gerund: decayendo
- Past participle: decaído
- Auxiliary verb: haber (all perfect tenses are formed with haber + decaído)
Pronunciation is not listed on this page: the verified tables do not include IPA for decaer, so no pronunciation is given rather than an invented one. Decaer follows caer: the present is decaigo and the preterite is decaí. The participle is regular in form but accented: decaído.
Full conjugation tables
Every form below comes from the verified conjugation tables for decaer. 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 | Form |
|---|---|
| yo | decaigo |
| tú | decaes |
| él/ella/Ud. | decae |
| nosotros/as | decaemos |
| vosotros/as | decaéis |
| ellos/ellas/Uds. | decaen |
Preterite
| Person | Form |
|---|---|
| yo | decaí |
| tú | decaíste |
| él/ella/Ud. | decayó |
| nosotros/as | decaímos |
| vosotros/as | decaísteis |
| ellos/ellas/Uds. | decayeron |
Imperfect
| Person | Form |
|---|---|
| yo | decaía |
| tú | decaías |
| él/ella/Ud. | decaía |
| nosotros/as | decaíamos |
| vosotros/as | decaíais |
| ellos/ellas/Uds. | decaían |
Future
| Person | Form |
|---|---|
| yo | decaeré |
| tú | decaerás |
| él/ella/Ud. | decaerá |
| nosotros/as | decaeremos |
| vosotros/as | decaeréis |
| ellos/ellas/Uds. | decaerán |
Conditional
| Person | Form |
|---|---|
| yo | decaería |
| tú | decaerías |
| él/ella/Ud. | decaería |
| nosotros/as | decaeríamos |
| vosotros/as | decaeríais |
| ellos/ellas/Uds. | decaerían |
Present perfect
| Person | Form |
|---|---|
| yo | he decaído |
| tú | has decaído |
| él/ella/Ud. | ha decaído |
| nosotros/as | hemos decaído |
| vosotros/as | habéis decaído |
| ellos/ellas/Uds. | han decaído |
Pluperfect
| Person | Form |
|---|---|
| yo | había decaído |
| tú | habías decaído |
| él/ella/Ud. | había decaído |
| nosotros/as | habíamos decaído |
| vosotros/as | habíais decaído |
| ellos/ellas/Uds. | habían decaído |
Future perfect
| Person | Form |
|---|---|
| yo | habré decaído |
| tú | habrás decaído |
| él/ella/Ud. | habrá decaído |
| nosotros/as | habremos decaído |
| vosotros/as | habréis decaído |
| ellos/ellas/Uds. | habrán decaído |
Conditional perfect
| Person | Form |
|---|---|
| yo | habría decaído |
| tú | habrías decaído |
| él/ella/Ud. | habría decaído |
| nosotros/as | habríamos decaído |
| vosotros/as | habríais decaído |
| ellos/ellas/Uds. | habrían decaído |
Present subjunctive
| Person | Form |
|---|---|
| yo | decaiga |
| tú | decaigas |
| él/ella/Ud. | decaiga |
| nosotros/as | decaigamos |
| vosotros/as | decaigáis |
| ellos/ellas/Uds. | decaigan |
Imperfect subjunctive (-ra)
| Person | Form |
|---|---|
| yo | decayera |
| tú | decayeras |
| él/ella/Ud. | decayera |
| nosotros/as | decayéramos |
| vosotros/as | decayerais |
| ellos/ellas/Uds. | decayeran |
Imperative (affirmative)
| Person | Form |
|---|---|
| tú | decae |
| él/ella/Ud. | decaiga |
| nosotros/as | decaigamos |
| vosotros/as | decaed |
| ellos/ellas/Uds. | decaigan |
Imperative (negative)
| Person | Form |
|---|---|
| tú | decaigas |
| él/ella/Ud. | decaiga |
| nosotros/as | decaigamos |
| vosotros/as | decaigáis |
| ellos/ellas/Uds. | decaigan |
Gerund and past participle
| Form | Spanish | Use |
|---|---|---|
| Gerund | decayendo | with estar for the progressive: estoy decayendo |
| Past participle | decaído | with haber for the perfect tenses: he decaído |
How to use each tense
Present indicative
Use the present for routines, general facts and what is happening right now. This tense is irregular for this verb: it follows the pattern of caer, with a -g- in the present (as in decaigo) and changes in the preterite and subjunctive. Learn the forms in the table rather than guessing them from the infinitive. For decaer, the present looks like this in a real sentence: Decaigo con la edad y la enfermedad. 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. This tense is irregular for this verb: it follows the pattern of caer, with a -g- in the present (as in decaigo) and changes in the preterite and subjunctive. Learn the forms in the table rather than guessing them from the infinitive. For decaer, the preterite looks like this in a real sentence: Ayer, decaí poco a poco tras la crisis. 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 decaer, the imperfect looks like this in a real sentence: De niño, decaía el interés por el proyecto. 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 decaer, the future looks like this in a real sentence: Mañana, decaeré la economía del país. 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 decaer, the conditional looks like this in a real sentence: Decaería con la edad y la enfermedad 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 decaer, the present perfect looks like this in a real sentence: Hoy, he decaído poco a poco tras la crisis. 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 decaer, the pluperfect looks like this in a real sentence: Había decaído el interés por el proyecto 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 decaer, the future perfect looks like this in a real sentence: Para mañana, habré decaído la economía del país. 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 decaer, the conditional perfect looks like this in a real sentence: Habría decaído con la edad y la enfermedad 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. This tense is irregular for this verb: it follows the pattern of caer, with a -g- in the present (as in decaigo) and changes in the preterite and subjunctive. Learn the forms in the table rather than guessing them from the infinitive. For decaer, the present subjunctive looks like this in a real sentence: Espero que él decaiga poco a poco tras la crisis. 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. This tense is irregular for this verb: it follows the pattern of caer, with a -g- in the present (as in decaigo) and changes in the preterite and subjunctive. Learn the forms in the table rather than guessing them from the infinitive. For decaer, the imperfect subjunctive looks like this in a real sentence: Si él decayera el interés por el proyecto, 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. This tense is irregular for this verb: it follows the pattern of caer, with a -g- in the present (as in decaigo) and changes in the preterite and subjunctive. Learn the forms in the table rather than guessing them from the infinitive. For decaer, the affirmative imperative looks like this in a real sentence: ¡Decae la economía del país! 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. This tense is irregular for this verb: it follows the pattern of caer, with a -g- in the present (as in decaigo) and changes in the preterite and subjunctive. Learn the forms in the table rather than guessing them from the infinitive. For decaer, the negative imperative looks like this in a real sentence: No decaigas con la edad y la enfermedad. 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 decaer, covering different tenses and persons. Each one uses a form from the tables above.
- Decaigo con la edad y la enfermedad. — I decline with age and illness.
- Decae poco a poco tras la crisis. — He/she declines little by little after the crisis.
- Ayer, decaí el interés por el proyecto. — Yesterday, I declined interest in the project.
- Antes, nosotros decaíamos la economía del país. — Before, we used to decline the country's economy.
- Mañana, tú decaerás con la edad y la enfermedad. — Tomorrow, you will decline with age and illness.
- Yo decaería poco a poco tras la crisis si tuviera más tiempo. — I would decline little by little after the crisis if I had more time.
- Él ha decaído el interés por el proyecto. — He has declined interest in the project.
- Espero que él decaiga la economía del país. — I hope he declines the country's economy.
- Yo ya había decaído con la edad y la enfermedad antes de salir. — I had already declined with age and illness before leaving.
- Ellos decaían poco a poco tras la crisis cuando eran jóvenes. — They used to decline little by little after the crisis when they were young.
Common mistakes
- Wrong: Yo decae con la edad y la enfermedad. — Right: Yo decaigo con la edad y la enfermedad. — The person matters: decae is the él/ella/Ud. form, while the yo form is decaigo. Using the third-person form with yo is one of the most common beginner errors.
- Wrong: Yo he decaido el interés por el proyecto. — Right: Yo he decaído el interés por el proyecto. — The past participle of decaer is irregular: decaído, not decaido. Every perfect tense uses he decaído, había decaído and so on.
- Wrong: Treating decaer and mejorar as identical in every context. — Right: Decaer means to decline, to weaken, while mejorar means to improve. — They overlap, but each has uses the other does not: decaer fits sentences such as Decaigo con la edad y la enfermedad, while mejorar belongs in a different sentence. Check the meaning you want before choosing.
- Wrong: Yo soy decaído poco a poco tras la crisis. — Right: Yo he decaído poco a poco tras la crisis. — Spanish perfect tenses use haber, not ser: he decaído, has decaído, ha decaído. Ser plus the participle makes a passive, not a perfect tense.
- Wrong: De niño, yo decaí el interés por el proyecto todos los días. — Right: De niño, yo decaía el interés por el proyecto todos los días. — For a repeated habit in the past, use the imperfect (decaía), not the preterite. The preterite (decaí) is for one finished action.
Quiz: test yourself
Ten questions on decaer. Choose the right form, then check the answer key below.
Complete the sentence: Yo ___ con la edad y la enfermedad. (present tense) A. decaigo B. decaes C. decae D. decaemos
Complete the sentence: Ayer, él ___ poco a poco tras la crisis. (preterite) A. decaí B. decaíste C. decayeron D. decayó
Complete the sentence: Antes, nosotros ___ el interés por el proyecto. (imperfect) A. decaías B. decaían C. decaíamos D. decaía
Complete the sentence: Mañana, tú ___ la economía del país. (future) A. decaeremos B. decaerás C. decaeré D. decaerá
Complete the sentence: Yo ___ con la edad y la enfermedad si pudiera. (conditional) A. decaería B. decaerías C. decaerían D. decaigo
Complete the sentence: Espero que él ___ poco a poco tras la crisis. (present subjunctive) A. decaigas B. decaigamos C. decaigo D. decaiga
Complete the sentence: Si yo ___ el interés por el proyecto, todo cambiaría. (imperfect subjunctive, -ra form) A. decayéramos B. decaigo C. decayera D. decayeras
Complete the sentence: Nosotros ___ la economía del país. (present perfect) A. han decaído B. hemos decaído C. he decaído D. has decaído
Complete the command: ¡___ con la edad y la enfermedad! (affirmative imperative, tú) A. decae B. decaiga C. decaigamos D. decaed
Which is the gerund of decaer, used with estar for the progressive? A. decaído B. decaigo C. decaí D. decayendo
Answer key
- decaigo — The first-person present of decaer is decaigo. The other options are the tú, él/ella and nosotros forms.
- decayó — The third-person preterite of decaer is decayó, the form for a single finished action in the past.
- decaíamos — The nosotros imperfect of decaer is decaíamos, used here for a repeated past habit.
- decaerás — The second-person future of decaer is decaerás.
- decaería — The first-person conditional of decaer is decaería, the form for what would happen.
- decaiga — After espero que, the subjunctive is required: the third-person present subjunctive of decaer is decaiga.
- decayera — The first-person imperfect subjunctive (-ra) of decaer is decayera.
- hemos decaído — The nosotros present perfect of decaer is hemos decaído: hemos + decaído.
- decae — The affirmative tú imperative of decaer is decae.
- decayendo — The gerund of decaer is decayendo: estoy decayendo. The participle decaído is used with haber instead.
Frequently asked questions
What does decaer mean in English?
Decaer means to decline, to weaken. It is used in everyday situations such as Decaigo con la edad y la enfermedad. The exact English wording depends on the context, but the core meaning stays the same across the tenses.
Is decaer regular or irregular?
Decaer is irregular in present, preterite, present-subjunctive, imperfect-subjunctive, imperative-affirmative, imperative-negative. The other tenses follow the regular pattern. Learn the irregular forms from the tables above rather than guessing them from the infinitive.
What is the difference between decaer and mejorar?
Decaer means to decline, to weaken, while mejorar means to improve. They are easy to confuse because they appear in similar situations, but they are not interchangeable: use decaer when you mean to decline, to weaken, as in Decaigo con la edad y la enfermedad, and use mejorar for to improve. When in doubt, check the object of the sentence — it usually shows which verb fits.
How do I say “I decline” in the past?
It depends on the kind of past. For one finished action, use the preterite: yo decaí poco a poco tras la crisis. For a repeated habit or background in the past, use the imperfect: yo decaía el interés por el proyecto. For something that has just happened, use the present perfect: yo he decaído poco a poco tras la crisis.
How do I practise decaer?
Start with the present tense table, then drill the preterite and the imperfect, since those two past tenses cause the most mistakes. Try the decaer examples and quiz page for more sentences, and use the Spanish Verb Quiz to test the forms under pressure.
Related links
- Decaer in the preterite tense — the full preterite-tense table for decaer.
- Decaer examples and quiz — more example sentences and practice for decaer.
- Spanish verbs — the Spanish hub, with every verb and tense guide.
- Complete list of Spanish irregular verbs — where this verb's pattern is listed.
- Recaer conjugation — another -er verb to compare with decaer.
- Sustraer conjugation — another -er verb to compare with decaer.
- Prever conjugation — another -er verb to compare with decaer.
- Spanish Verb Conjugator — conjugate any Spanish verb in every tense.
- Spanish Verb Quiz — test yourself on real conjugated forms.