How much food should I be eating as a female to gain weight/build muscle?

I'm naturally thin, 5'6 and 113 lb and 16 y/o, and I want to gain some weight. When I calculate my BMR, it ranges from 1300 to 1800 on different websites, so I don't know how much of a calorie surplus I should do. I exercise 4-6 days a week. Any recommendations?

from Bodybuilding.com Forums - Nutrition https://bbcom.me/2TaUA5w