From multiples to mortgages that are made to measure

Not so.

Lenders have traditionally based their decision on how much to advance on fairly strict income multiples, stipulating that you can borrow only three-and- a-half times your own gross salary - or two-and-a-half times a joint wage.

But thanks to the house price inflation of the past 10 years, the average home now sells for around £157,000, according to the Halifax. That leaves a buyer needing to earn £44,900 to qualify - nearly double the national average salary.

Now, however, with interest rates less volatile, more lenders are easing their reliance on borrowing multiples and adopting a new criterion: "affordability". Under this system, disposable income and personal circumstances are taken into account.

"Affordability will take into account your credit score, how much you spend every month, your net income [after bills and debt] and, say, if you have children living with you," says Melanie Bien, associate director of broker Savills Private Finance. As a rule, if you're a good risk, you'll be lent a lot more than with income multiples - as much as five or six times your salary - and be able to afford homes previously out of your reach.

Last month, Alliance & Leicester (A&L) became the latest lender to adopt affordability for its home loan calculations, following the likes of the Halifax, Nationwide and Abbey.

Each lender has its own formula, says Ian Giles at broker Purely Mortgages, but individual circumstances will be the key.

"We manage to get up to six times income [for borrowers] where, for example, they have a frugal lifestyle with few other commitments," he says. "Single people with no dependants and no other loans stand to benefit the most."

Although affordability has critics who believe loans of five times salary are irresponsible, there are plenty who defend it. "Why was it all right to lend 3.5 times in the early 1990s when interest rates were 15 per cent, but it's now not all right to lend five times income when rates are under 5 per cent?" asks Simon Tyler at broker Chase de Vere Mortgage Management. Affordability, won't be the best approach for everyone, though. People with high salaries, but high outgoings too, may well get a bigger loan using multiples.

But remember, calculations of maximum loans made on lenders' websites are just a rough guide. Based on a single income of £48,000 with no debts, you will be given a range of figures by the Halifax - from a minimum of £119,970 to a maximum of £191,951. At Northern Rock, the range will be £220,800 to £244,800.

Louise Cuming, at the price-comparison website moneysupermarket.com, warns that you can only get a definitive top figure from a website after a "score card" is applied - and this includes a credit check.

Be aware, though, too many searches "can damage your rating, reducing the amount you might be able to borrow," warns Mr Tyler.

Simon and Vanessa Guy, from Reading, recently took out an affordability loan with Nationwide.

With Vanessa at home looking after their children, Chloe and Sophie, they were having trouble getting much of a loan on just one income. "The building society took account of the fact I work overtime, and offered us a good deal," he says.