At what level does Eevee evolve?

Answer 1

Evee evolves in many different ways here are all the ways to evolve it: Use a water stone, use a thunder stone, use a fire stone, max out friendship during the day, max out friendship during nighttime, max out friendship near the moss rock in diamond, pearl and platinum, max out friendship near the ice rock in diamond, pearl and platinum.
Eevee doesn't evolve at a particular level. As of Generation VI, here are the ways Eevee can evolve:

Vaporeon: Use a Water Stone

Flareon: Use a Fire Stone

Jolteon: Use a Thunder Stone

Espeon: Level up (to any level) with high friendship during the morning/day.

Umbreon: Level up (to any level) with high friendship at night.

Leafeon: Level up (to any level) near a Mossy Rock.

Glaceon: Level up (to any level) near an Ice Rock.

Sylveon: Level up (to any level) while knowing a Fairy move and having at least two hearts on Pokemon-Amie.

Answer 2

IT has no level you evolve it by giving it a stone such as Fire stone, Water stone, and all the others. Google or search eevee's evolutions too.