if I want to formally say, "I missed you" to someone

Question

to someone who has been away on vacation

Answer 1

le echo de menos a usted (singluar) los echo de menos a ustedes (plural)

le extraño a usted (singular) los extraño a ustedes (plural)

Answer 2

Whilst your answers are correct, the poster wanted the "formal" address NOT the "informal" address.

Answer 3

más informal: te extraño.

Answer 4

Te he extrañado = i missed you te echo de menos = i miss you

Answer 5

Te eché de menos= I missed you. Voy a echarte de menos= I am going to miss you. Te echo de menos = I miss you. Ken.