Most people don't understand the true meaning where it quotes things like "2000% apr"
eg - if someone got a payday loan for £500 and had to pay back £750 then that would be 50% interest
If they had to pay the loan back within 1 week (as it is a payday loan) then there are 52 weeks in a year so the 50% refers to the interest which is due in the 7 day period would equate to 50% * 52 weeks = 2600% apr (annual percentage rate) so therefore they are quoting what it would be if it was a loan which was spread over the 52 weeks (annual)
It is calculated as annual percentage rate, but alot of loans eg provident,payday loans etc are paid back much sooner than a year so the loan percentage rate is multiplied to reflect the annual percentage rate (apr)
Hope this clears this up and people now understand it better