If you work 40 hours per week, 52 weeks a year, you'll work 2080 hours. Factor in time off and extra hours, a good estimate is 2000 hours per year. If you make $20 per hour, that's about $40,000 per year.
To determine how much you make a year by your hourly wage, you first multiply your hourly wage by how many hours you work a week. Then you multiply that number by 52 weeks, this is how much you make in a year.