'Tan' and 'Tanto'

Both Words Used in Making Comparisons

Money from Mexico and Central America
Tengo tanto dinero como Juan. (I have as much money as Juan.). Fernando Reyes Palencia/Creative Commons

Tan and tanto can be a source of confusion in Spanish because they both can used in comparisons such as "as green as" and "as much as." But the two words, although closely related, are used in grammatically different ways and can't be substituted for each other.

One way to think of the main difference between the two is that tan is used as an adverb in those constructions, while tanto is used as an adjective. For this reason, tan doesn't change with the context, while tanto can also exist in the inflected forms tanta, tantos, and tantas.

Using Tan

Tan basically means "so," sometimes "such a" or "as," and is used only before adjectives or adverbs (or nouns used as adjectives). Examples: Rita es tan alta como María. (Rita is as tall as María.) Rita habla tan rápido como María. (Rita talks as fast as María.) Sentences like those are by far the most common usage of tan.

The phrase qué tan ​can often be translated as "how": ¿Qué tan inteligente eres? (How intelligent are you?)

Using Tanto

Tanto basically means "so much" or "so many" or, when used with como, "as much" or "as many." Examples: Tengo tanto dinero como Juan. (I have as much money as Juan.) Tengo tanto dinero que no sé qué hacer con él. (I have so much money I don't know what to do with it.)

Tanto also can be used to make other kinds of comparisons and has a wide variety of colloquial uses; under some circumstances it can be used not only as an adjective but also as a noun, pronoun or adverb. A good dictionary will list at least two dozen different uses. Examples: Tengo quince y tantos nietos. (I have 15 or so grandchildren.) No quiero estudiar tanto. (I don't want to study so much.) No como tanto ella. (I don't eat as much as she.)

Sample Sentences Using Tan and Tanto

El troll de Facebook dice: "Tan importante soy que me tienen que bloquear para ser feliz." (The Facebook troll says: I am so important that they have to block me to be happy.)

México está tan listo como Panamá. (Mexico is as ready as Panama.)

El centro de la Tierra está tan caliente como el Sol. (The center of the Earth is as hot as the sun.)

Descubre qué tan hombre eres con este machómetro. (Find out how much of a man you are with this macho-meter. This sentence construction, which is unusual, is an exception to the rule that tan isn't used with nouns.)

¡Qué tiempo tan feliz! (What a very happy time!)

Voy a ser tan rica como pueda. (I'm going to be as rich as I can.)

Dime tu estilo de crianza y te diré qué tan exitoso podría ser tu hijo. (Tell me your parenting style and I'll tell you how successful your child could be.)

¿Es necesario consumir y comprar tanto para ser feliz? (Is it necessary to consume and buy so much to be happy?)

¡Tengo tanto para hacer! (I have so much to do!)

Nunca se vendieron tantos coches eléctricos como en mayo. (They've never sold so many electric cars as in March.)

Es irónico cómo la vida te da tanta felicidad y luego te llena de tanta tristeza. (It's ironic how life gives you so much happiness and later fills you with so much sadness.)

Hay días que no quiero nada, pero necesito tanto. (There are days that I don't want anything, but I need so much.)

Tanto ella como su marido recibieron la noticia con entusiasmo. (She as much as her husband enthusiastically received the news.)

Después de tantos días perfectos, empecé a creer que toda la vida sería así. (After so many perfect days, I began to believe that all of life would be like that.)

El amor durará tanto como lo cuides, y lo cuidarás tanto como lo quieras. (Love will endure as much as you nurture it, and you will nurture it as much as you want it.)