^ $15 on $100 over 14 days is ratio of 15/100 = 0.15, so this is a 14-day rate. Over a year (365.25 days) this 14-day rate can aggregate to either 391% (assuming you carry the $100 loan for a year, and pay $15 every 14 days: 0.15 x (365.25/14) = 3.91, which converts to a percentage increase (interest rate) of: 3.91 x 100 = 391%) or 3733% (assuming you take out a new loan every 14 days that will cover your principal and "charge", and every new loan is taken at same 15% "charge" of the amount borrowed: (1 + 0.15)365.25/14 − 1 = 37.33, which converts to a percentage increase (interest rate) of: 37.33 x 100 = 3733%).
Keep in mind that even the best payday lender is still extremely expensive, and you should try to find other options before visiting one. Fees vary depending on state regulations. In some states, such as Oregon, you pay around $13 for every $100 you borrow. In other states, such as Texas and Wisconsin, Check Into Cash charges $25 for every $100 you borrow. This puts the lender at about the industry average for payday loan fees. It doesn’t appear to take advantage of states with less stringent payday lending laws like Utah. We didn’t see fees greater than $25, which, while expensive, isn’t the highest we saw in our research.