The average cost of a wedding now stands at more than £17,000, but couples planning to tie the knot think their big day will set them back just £6,650, the Alliance & Leicester study shows.
This gross misjudgement means some 17 per cent of couples are forced to borrow money to pay for wedding costs, as the majority now try and pay their own way.
The need to borrow substantial sums of money ahead of their wedding day was cited by one in five couples as their biggest worry before tying the knot.
Claire Alvey, personal loans manager for Alliance & Leicester, commented: “If you are going to borrow money to pay towards the big day, make sure you take the time to get a good deal.
“You could be making unnecessary overpayments on higher interest rates. You might as well tear up the cash and use it as confetti.”