Expressions of quantity: mucho, poco, bastante, demasiado

Tengo mucho trabajo, pero bastante tiempo.I have a lot of work, but enough time.

Spanish has a small set of words for talking about how much or how many of something there is — some of them change their ending to match the noun, and some never change at all. Knowing which is which clears up one of the most common beginner mixups in Spanish.

Quick shortcut: mucho/poco/demasiado agree with the noun they describe (mucha agua, pocos libros); bastante only agrees in number, never gender (bastante tiempo, bastantes amigos). Modifying a verb, all four freeze into one invariable form.

As adjectives: agreeing with the noun

Mucho dinero (a lot of money), mucha gente (a lot of people), muchos libros (a lot of books), muchas preguntas (a lot of questions). Poca leche (little milk), pocos amigos (few friends). Bastante tiempo (enough time), bastantes personas (enough people) — bastante only ever changes for plural, never for gender, so bastante tiempo and bastante suerte keep the same ending even though tiempo is masculine and suerte is feminine. Demasiados problemas (too many problems), demasiada sal (too much salt).

All four go directly before the noun, with no article in between: tengo mucho trabajo, never ❌ tengo mucho el trabajo.

As adverbs: modifying a verb

Right after a verb, all four stay invariable, regardless of who or what is doing the action — for mucho, poco and demasiado that single form is the masculine singular; bastante never had a separate masculine/feminine form to begin with, so there's nothing to freeze there.

Ella trabaja mucho. (She works a lot.) Los niños comen poco. (The kids eat little.) Hemos viajado bastante. (We've traveled enough.) Duermes demasiado. (You sleep too much.)

Ella trabaja mucho keeps mucho, not ❌ mucha, even though ella is feminine — here mucho is describing the verb trabaja, not agreeing with a noun.

mucho vs. muy before an adjective or another adverb

This is the trap almost every beginner falls into. Right before an ordinary adjective or another adverb, mucho changes to muy — a completely different word, not just a different ending.

✅ Estoy muy cansada. (I'm very tired.) ❌ Estoy mucho cansada. ✅ Habla muy rápido. (He speaks very fast.) ❌ Habla mucho rápido.

Bastante and demasiado, on the other hand, go straight in front of an adjective with no change at all:

Es bastante caro. (It's quite expensive.) Es demasiado caro. (It's too expensive.) Son bastante altos. (They're quite tall — bastante stays invariable here too, exactly like muy, because it's modifying the adjective altos, not agreeing with the subject.)

The one exception: before a comparative, mucho stays mucho rather than becoming muy — mucho mejor (much better), mucho más fácil (much easier), mucho menos rápido (much less fast). Muy is for an ordinary adjective/adverb; a comparative one keeps mucho.

So the one word that behaves differently depending on position is mucho: it's mucho before a noun, after a verb, or before a comparative, but muy before an ordinary adjective or adverb. Bastante and demasiado only ever change form to agree with a noun they describe directly (bastantes amigos, demasiados problemas) — before an adjective or adverb they freeze, just like muy.

un poco de + noun: a small amount

Un poco de narrows poco down to "a bit of," combined with a noun — most often an uncountable one — and never changing form itself:

Quiero un poco de agua. (I want a bit of water.) Añade un poco de sal. (Add a bit of salt.)

Compare this to plain poco/poca without un, which tends to read as "not much/not enough," often with a hint of insufficiency depending on context:

Tengo poco dinero. (I have little money — can suggest that's a problem.) Tengo un poco de dinero. (I have a bit of money — just states the small amount, with no such implication.)

Common mistakes

• ❌ Estoy mucho cansado. → ✅ Estoy muy cansado. (before an adjective, mucho becomes muy — it never modifies an adjective directly.)
• ❌ Ella trabaja mucha. → ✅ Ella trabaja mucho. (modifying a verb, mucho is invariable — it doesn't agree with the subject.)
• ❌ Tengo bastantes tiempo. → ✅ Tengo bastante tiempo. (bastante only changes for plural nouns, not for gender — tiempo is singular here.)
• ❌ Hay mucho el ruido. → ✅ Hay mucho ruido. (no article between a quantity word and the noun.)

Quick check

1. Fill the blank: Tengo ___ hambre. (a lot of)
2. Fill the blank: Estoy ___ ocupada hoy. (very)
3. What's wrong with Comen mucha (meaning "they eat a lot"), and how would you fix it?
4. Say "I have enough friends" using bastante.

Key takeaways

• Mucho, poco and demasiado agree in gender and number with the noun they describe; bastante only ever agrees in number.
• Right after a verb, all four stay invariable, regardless of who's doing the action.
• Before an ordinary adjective or adverb, mucho becomes a different word, muy — except before a comparative, where it stays mucho (mucho mejor). Bastante and demasiado stay exactly as they are in every case.
• Un poco de + noun means "a bit of," most often with an uncountable noun, and never changes form; plain poco/poca without un tends to suggest "not enough."