It's a sensible question – while in theory, lenders have to take steps to ensure you can afford to keep up the monthly repayments (as much for their own sake as yours), buyers can still end up saddled with a mortgage they can't afford. Even if you have a stable income and can comfortably afford a mortgage now, it pays to think about what would happen if your circumstances changed.

There are a number of mortgage calculators online, such as the one provided by SPF, which give a good general idea of how much a mortgage will cost per month, taking into account the price of the property, the deposit available, the length of the mortgage and the rate of interest. Unless you're on a fixed rate, the rate of interest – and with it your monthly repayments – could change over time, and it's worth doing the maths to find out whether you could still afford it if interest rates rise.

Mortgage calculators don't usually factor in the other costs associated with a mortgage, such as arrangement fees, valuation fees, stamp duty and so on, and while these are mostly one-off costs, they still need to be considered when deciding whether you can afford a mortgage. They will all be tabled in a mortgage illustration document which your lender should provide.

The terms of the mortgage may also affect your decision: are there missed payment fees or early repayment charges? The latter could be significant if, for example, you're planning to use part of your pension to pay off your mortgage early. And if you're getting one of the less common types of mortgage, such as an offset, you will need to consider whether you can afford to devote enough of your savings to make it worthwhile.

There's no hard and fast rule to deciding whether you can afford a mortgage: a lot will depend on your lifestyle, your assets, the amount of disposable income you have and the stability of your income (and your partner's, if you're getting a joint mortgage). Everybody has a different idea of how much they need to be comfortable – and even if you can afford it, will it affect any other plans you've made over the next few years?

As a rule, if you can only just afford a mortgage – if you generally earn enough to make the repayments, but it'll put your finances on something of a knife-edge – you may want to think again. A mortgage should be a source of security, not stress, and however much you may have fallen in love with a property, very few are worth losing your financial freedom for.

Further information

For more advice, contact Savills Finance or view available properties for sale

The house-buying process explained