Spanish Accent Marks (Tildes): The Simple Rules for Knowing Where They Go

If you’ve ever stared at a Spanish word and wondered whether it needs that little slanted mark — tilde — before you write it, you’re not alone. Most learners treat accent marks as decoration they’ll “get around to,” until a mistake changes the meaning of what they actually said (more on that below). The good news: Spanish accentuation follows real, learnable rules. There’s no guessing involved, once you know where to look.

Step One: Find the Stressed Syllable

Every Spanish word of more than one syllable has one syllable that’s pronounced with more force — the stressed syllable. Say the word out loud and listen for it: in ca-SA, the stress falls on the second syllable; in LÁ-piz, it falls on the first. The entire system of tildes exists to mark where that stress falls when it doesn’t fall where Spanish expects it to by default.

That’s the part most courses skip, and it’s the key to everything else: a tilde isn’t random decoration, it’s a flag saying “the stress is somewhere unusual — pay attention here.”

The Three Word Types That Explain (Almost) Everything

Spanish classifies words by where the stress naturally falls, counting from the end of the word.

Agudas (stress on the last syllable)

Get a tilde only if they end in n, s, or a vowel — because those endings are exactly the ones where Spanish normally expects the stress on the second-to-last syllable, not the last. Examples: sofá, canción, autobús, café. Compare with reloj, feliz, ciudad — agudas too, but no tilde needed, because they don’t end in n, s, or a vowel, so the stress falling on the last syllable is already the default.

Llanas (stress on the second-to-last syllable)

Get a tilde only if they do NOT end in n, s, or a vowel — the exact opposite rule, because this is the default pattern for words ending any other way. Examples: árbol, difícil, azúcar, césped. Words like casa, mesa, libros are llanas too, but need no tilde, since ending in a vowel or s already matches the expected pattern.

Esdrújulas (stress on the third-to-last syllable)

Always get a tilde, no exceptions. This stress pattern is rare enough in Spanish that it always needs flagging. Examples: música, teléfono, rápido, brújula, gramática.

Notice the logic ties together: agudas and llanas follow opposite endings rules, and esdrújulas are simply always marked because that stress pattern never happens “by default.”

One-Syllable Words: The Exception That Proves the Rule

Words with a single syllable generally don’t carry a tilde at all — there’s nowhere else the stress could fall. But Spanish makes a deliberate exception when two one-syllable words are spelled identically but mean different things. The tilde here isn’t about pronunciation; it’s purely to tell two words apart on the page: