For 2013, the maximum you can contribute to all of your traditional and Roth IRAs is the lesser of:
$5,500 ($6,500 if you're age 50 or older), or
100% of earned income or compensation
For 2013, the maximum a self-empoyed person or business owner can contribute to an employee's SEP IRA is the lesser of:
25% of the employee's compensation, or
$51,000