When should you use "cuanto" and "cuánto"?
A simple little line over a letter can have so much power. The use of the acento in Spanish has left many language learners in dire straits. Things get especially tricky when the word with the acento has a naked little counterpart. One of these cheeky words is cuanto/cuánto. But fret not! In this post, we will dive deep into the different uses (yes, there are more than two) of these words.
As a basic rule, cuánto has an accent when used in an interrogative or exclamative context. In that case, it will become an interrogative/exclamative pronoun. It can also be used as an interrogative/exclamative adjective when paired with a noun. Cuanto, its nudist brother, is used when it acts as an adjective or adverb. Here it would be a relative pronoun that introduces subordinate clauses or make comparisons of equality. But hold on. That doesn’t mean that cuanto can’t be in a question/exclamation. Now that you're cooking with frustration, let's check out some examples to ease the tension:
No accent
Comparison
In this case, it should either replace "all that", or to make comparisons of equality.
Cuanto más quieres a alguien, más te importa. = The more you love someone, the more you care about them.
Everything/Anything
Here, it's a relative adjective introducing a subordinate clause.
Mi madre me deja hacer cuanto yo quiera. = My mom lets me do everything I want.
Accent
How many/How much
¿Cuánto cuesta? = How much is it?
How long
¿Hace cuánto que llueve? = How long has it been raining?
So many/So much/How many/How much/What a lot of
¡Cuánta alegría! = It makes me so happy! (lit. how much happiness!)

Common expressions
Let's look at some common sentences you'd use in your day-to-day life:
¿Cada cuánto…? = How often?
¿Cuánto es (1 más 1)? = How much is 1 plus 1?
¿Cuánto por todo? = How much for all of it?
¿Cuánto falta para…? = How close are we to…?
¿Cuánto le debo? = How much do I owe you?
¿Cuánto tiempo lleva…? = How long has it been…?
¿Dentro de cuánto tiempo…? = How soon…?
¿A cuánto…? = How much is / are…? (these are all questions, so we use cuánto.)
Cuanto antes. = As soon as possible.
Cuanto más. = The more.
Cuanto(s) más, mejor. = The more, the merrier. (No questions here, these are just statements.)
Cuánto me alegro. = I am so glad. (Although this expression is written without question marks, it is indeed still a question. The literal translation is "how happy am I?", but it's used rhetorically. Because you can't believe how happy I am! Rhetoric or literal, a question remains a question, so cuánto is required.)
En cuanto. = When/As soon as
En cuanto a. = Regarding.
En cuanto a mí. = As for me.
En cuanto sea posible. = As soon as possible.
I hope this has helped you gain a more solid understanding of cuando (oh, another one...?) you should use cuanto and cuánto. If you have any more questions, leave a comment on the social post or send me a quick message. I'm always happy to help language learners achieve their goals!