Introduction
Fundir means “to melt, to merge”, and it is one of the verbs you will use again and again in Spanish. Fundir means to melt or to merge, and it covers melting metal, ice and cheese, and merging two companies: fundir el hierro, fundirse con otra empresa. It is a regular -ir verb. This page shows fundir in real sentences, in short dialogues, and in the mistakes learners make most often, and it finishes with a ten-question quiz so you can test yourself. Every sentence below comes with its English translation, and every form is the correct present-tense form unless the sentence is clearly marked as past or future. For a first taste: “Fundo el hierro en el horno.” — I melt iron in the furnace.
Fundir in real example sentences
The twelve sentences below are grouped by how fundir is used. Read each one out loud, then read the translation. If a sentence feels useful, copy it into your own notebook with one small change — a different time, a different person, a different place — and you have a new sentence of your own.
In the present: everyday use
These sentences use fundir in the present tense, which is how you will meet it most often: routines, facts, and things happening now.
“Fundo el hierro en el horno.” — I melt iron in the furnace.
“¿Fundes el hielo con el calor?” — Do you melt ice with the heat?
“Funde dos empresas en una.” — He/she melts two companies into one.
“Nosotros fundimos el queso en la pizza.” — We melt cheese on the pizza.
Talking about the past
The present is not the only tense you need. These sentences show fundir in the past, so you can talk about what already happened.
“Ayer, yo fundí el hierro en el horno.” — Yesterday, I melted iron in the furnace. (preterite)
“Antes, él fundía el hielo con el calor.” — Before, he used to melt ice with the heat. (imperfect)
Plans and things already done
These sentences look forward, or look back at something already finished. Notice how the verb form changes while the meaning of fundir stays the same.
“Mañana, nosotros fundiremos dos empresas en una.” — Tomorrow, we will melt two companies into one. (future)
“¿Tú has fundido el queso en la pizza?” — Have you melted cheese on the pizza? (present perfect)
More everyday uses
Four more present-tense sentences, covering the remaining persons, so you can see the whole table in action.
“Vosotros fundís el hierro en el horno.” — You melt iron in the furnace.
“Ellos funden el hielo con el calor.” — They melt ice with the heat.
“Yo fundo dos empresas en una.” — I melt two companies into one.
“Mi padre funde el queso en la pizza.” — My father melts cheese on the pizza.
Fundir in context
Single sentences teach you the forms. Dialogues teach you when to use them. Read the short conversation below, then the paragraph that follows, and notice how fundir appears naturally, without anyone stopping to think about conjugation.
A short dialogue
Marta: “¿Tú fundes el hielo con el calor?” — Do you melt ice with the heat?
Pedro: “Sí, yo fundo el hierro en el horno.” — Yes, I melt iron in the furnace.
Marta: “Nosotros fundimos el queso en la pizza.” — We melt cheese on the pizza.
Pedro: “Y ellos funden el hielo con el calor.” — And they melt ice with the heat.
Marta: “Vosotros fundís dos empresas en una.” — You melt two companies into one.
Pedro: “Sí, y él funde el hierro en el horno.” — Yes, and he melts iron in the furnace.
A short paragraph
Funde el hierro en el horno, y nosotros fundimos el queso en la pizza. Yo fundo el hielo con el calor, y ellos funden dos empresas en una. Fundir is part of everyday life, because melt, to merge is something people do in work, at home and with friends, in the present, the past and the future.
Common mistakes with fundir
These are the errors learners actually make with fundir. Each one shows the wrong version, the right version, and why the correction matters.
Wrong: “Yo funde el hierro en el horno.” Right: “Yo fundo el hierro en el horno.” Why: The person matters: funde is the él/ella/Ud. form, while the yo form is fundo. Using the third-person form with yo is one of the most common beginner errors.
Wrong: “Ayer yo fundo el hielo con el calor.” Right: “Ayer yo fundí el hielo con el calor.” Why: The present and the preterite are different tenses: fundo is happening now, while fundí is a finished action in the past. Use the preterite with ayer.
Wrong: “Treating fundir and derretir as identical in every context.” Right: “Fundir means to melt, to merge, while derretir means to melt.” Why: They overlap, but each has uses the other does not: fundir fits sentences such as Fundo el hierro en el horno, while derretir belongs in a different sentence. Check the meaning you want before choosing.
Wrong: “Yo soy fundido el hielo con el calor.” Right: “Yo he fundido el hielo con el calor.” Why: Spanish perfect tenses use haber, not ser: he fundido, has fundido, ha fundido. Ser plus the participle makes a passive, not a perfect tense.
Wrong: “De niño, yo fundí dos empresas en una todos los días.” Right: “De niño, yo fundía dos empresas en una todos los días.” Why: For a repeated habit in the past, use the imperfect (fundía), not the preterite. The preterite (fundí) is for one finished action.
Quiz: fundir in use
Ten questions on fundir in real sentences. Choose the correct answer for each one, then check the answer key. Every answer is explained.
1. Complete the sentence: “Vosotros ______ el hierro en el horno.” (You melt iron in the furnace.)
- (a) fundís
- (b) fundo
- (c) fundes
Answer: fundís — The vosotros/as form of fundir in the present tense is fundís.
2. Complete the sentence: “Ellos ______ el hielo con el calor.” (They melt ice with the heat.)
- (a) fundes
- (b) funden
- (c) fundo
Answer: funden — The ellos/ellas/Uds. form of fundir in the present tense is funden.
3. Complete the sentence (preterite): “Ayer yo ______ el hierro en el horno.” (Yesterday I melted iron in the furnace.)
- (a) fundiste
- (b) fundió
- (c) fundí
Answer: fundí — In the preterite, the yo form of fundir is fundí.
4. Complete the sentence (imperfect): “Antes, él ______ el hielo con el calor.” (Before, he used to melt ice with the heat.)
- (a) fundía
- (b) fundo
- (c) fundías
Answer: fundía — In the imperfect, the él/ella/Ud. form of fundir is fundía.
5. Complete the sentence (future): “Mañana, nosotros ______ dos empresas en una.” (Tomorrow we will melt two companies into one.)
- (a) fundirás
- (b) fundiremos
- (c) fundiré
Answer: fundiremos — In the future, the nosotros/as form of fundir is fundiremos.
6. What does fundir mean in English?
- (a) to melt, to merge
- (b) to flow
- (c) to melt
Answer: to melt, to merge — Fundir means “to melt, to merge”. The other options are the meanings of different verbs.
7. Which sentence is correct?
- (a) Yo funde el hierro en el horno.
- (b) Ellos funde el hielo con el calor.
- (c) Yo fundo el hierro en el horno.
Answer: Yo fundo el hierro en el horno. — “Yo fundo el hierro en el horno.” is correct. The other two sentences contain the mistakes explained in the section above.
8. How do you say “I melt iron in the furnace.” in Spanish?
- (a) Mi padre funde el queso en la pizza.
- (b) Fundo el hierro en el horno.
- (c) Funden el hierro en el horno.
Answer: Fundo el hierro en el horno. — “Fundo el hierro en el horno.” is the correct translation.
9. What is the nosotros form of fundir in the present tense?
- (a) fundo
- (b) fundes
- (c) fundimos
Answer: fundimos — The nosotros form is fundimos.
10. Which of these sentences is in the present tense?
- (a) Mañana, nosotros fundiremos dos empresas en una.
- (b) Fundo el hierro en el horno.
- (c) Ayer, yo fundí el hierro en el horno.
Answer: Fundo el hierro en el horno. — “Fundo el hierro en el horno.” is in the present tense. The other two are in the preterite and the future.
Frequently asked questions
How do you say 'I melt iron in the furnace' in Spanish?
Say 'Fundo el hierro en el horno'. For a routine, add a time expression: 'Fundo el hierro en el horno todos los días'.
How do you say 'He melts ice with the heat' in Spanish?
Say 'Él funde el hielo con el calor'. The subject comes first, and the verb agrees with it: él takes funde.
What is the difference between fundir and derretir?
Fundir means to melt, to merge, while derretir means to melt. They are easy to confuse because they appear in similar situations, but they are not interchangeable: use fundir when you mean to melt, to merge, as in 'Fundo el hierro en el horno', and use derretir for to melt.
Related pages
- Full conjugation of fundir — every tense of fundir in one place.
- Fundir in the present tense — the full table and usage rules for one tense.
- Spanish verbs — the hub for every Spanish verb on VerbFlow.
- Verb quiz — test yourself on fundir and other verbs.
- Conjugation practice — drill the forms of fundir until they are automatic.