The number and level of mortgage fees charged by lenders has leapt since the beginning of the financial crisis, with 39 different fees now used, according to Which? Money.
Research by the consumer champion revealed that building societies charge the most types of fees, with Newcastle Building Society topping the chart with 29 fees, followed by Ipswich Building Society with 28.
Coventry, West Bromwich and Leek United Building Societies all charge 27 types of fees, while Yorkshire Building Society has 25 alongside Britannia and the Co-operative Bank.
Big name lenders Halifax and Northern Rock have 21 fees, while Lloyds TSB and Santander have 18.
Stafford Railway had the fewest fees at three, followed by First Direct with five types of fee and HSBC with four.
Which? Money said that the variety of fees was making comparing mortgages a much more complex business.
It found that last year 81.5% of two-year tracker mortgages up to 90% loan-to-value (LTV) charged more than £990 in set-up fees compared to 20% in 2007.
In addition, just 3.7% of two-year trackers at 90% LTV were fee-free in 2010, compared to 24.4% in 2007.
Which? Money, which looked at more than 1,100 fixed rate and tracker mortgages, highlighted that set-up and additional fees could range from booking and arrangement fees to arrears charges and payments for switching from an interest-only to repayment deal.
James Daley, editor of Which? Money, said: "Finding the right mortgage used to be as simple as looking for the best rate but the array of fees nowadays has made it a much harder task - it's never been more difficult to understand how much a mortgage is going to cost.
"Lenders should make it clear what the total cost of a deal is so borrowers can make easy comparisons."