Explanation

Quick Answer

Comparisons of equality are used to say that two nouns are equal to one another in some way.

Tan Comparisons

To compare two nouns, you can use tan (so) with an adjective or adverb. Here is the formula for tan comparisons.

tan + adjective/adverb + como

For example:

examples
Sara es tan alta como tu hermano. Sara is as tall as your brother.
Tu coche corre tan rápido como su coche. Your car goes as fast as his car.

The adjective in a tan comparison must match the subject of the sentence in gender and number.

examples
Mi hermana es tan alta como tu hermano. My sister is as tall as your brother.
Mi hermano es tan alto como tu hermano. My brother is as tall as your brother.
Mis hermanas son tan altas como tu hermano. My sisters are as tall as your brother.
Mis hermanos son tan altos como tu hermano. My brothers are as tall as your brother.

You also use tanto (so many/so much) to form comparisons of equality using a noun. Here is the formula for tanto comparisons.

tanto + noun + como

For example:

examples
Mi perro tiene tanto pelo como mi gato. My dog has as much fur as my cat.
Tenemos tanto trabajo como ustedes. We have as much work as you guys do.

The word tanto must match the noun that follows it in gender and number.

examples
Tengo tanto dinero como Alicia. I have as much money as Alicia.
Mi madre tiene tanta paciencia como ella. My mother has as much patience as her.
Tiene tantos plátanos como él. He has as many bananas as him.
Quiero tantas manzanas como ella. I want as many apples as her.