Polite Ways to Say "Thank You" in Spanish

The everyday expression is "gracias"; to make it sound softer or more formal, use "muchas gracias", "se lo agradezco mucho" or "muy amable".

The most common way

Thank you; the neutral, everyday way to express gratitude.

How to say it: In most of Spain the "c" in "gracias" sounds like the "th" in "think"; in Latin America it is usually an "s". Stress the first syllable: GRA-cias.

Other ways to say it

standard, warmer

Thank you very much; the normal way to add warmth and avoid sounding curt.
When to use it: Use it in almost any polite situation, especially with strangers, staff, or acquaintances.
formal

I really appreciate it; a formal, respectful thank-you.
When to use it: Use it with someone you address as "usted", such as a boss, official, or older stranger.
polite, kind

That's very kind of you; a brief polite acknowledgment of a favour or offer.
When to use it: Say it after someone helps you, offers a seat, or does a small courtesy, often alongside "gracias".
heartfelt, informal

I really appreciate it; sincere and personal, not stiff.
When to use it: Use it with friends, close colleagues, or people you address as "tú".
strong, formal

I can't tell you how much I appreciate it; a strong formal thank-you for significant help.
When to use it: Use it with someone you address as "usted" when they have done something important for you.
casual, warm

Thanks a million; warm and slightly informal, not slang.
When to use it: Use it with friends, colleagues, or in relaxed service situations, not in very formal writing.

In a conversation

A
, .
Excuse me, you've dropped your umbrella.
B
. .
Thank you very much. That's very kind.
A
.
You're welcome.

Common mistakes

~~Muy gracias~~ → Muchas gracias
Spanish uses "muchas" with "gracias", not the adverb "muy".
~~Gracias mucho~~ → Muchas gracias
The natural quantifier is "muchas", not the adverb "mucho".