Fixed rate mortgage is ideal for buyers who don't want a nasty surprise should interest rates rise – but you'll pay for the privilege. Fixed rate deals tend to have higher APRs than variable rate mortgages, and of course if interest rates fall then you might end up paying over the odds.

Variable rate mortgages are usually the cheapest products with the lowest interest rates, but there's a risk: if interest rates rise, so do your monthly payments. A fixed rate mortgage protects you from these nasty surprises, and most lenders will fix the interest rate for a period of two, three or five years.

A fixed rate mortgage makes most sense when, like now, interest rates are low: should interest rates rise, you'll be paying considerably less money than you would with a variable rate mortgage. Of course the reverse applies too, so it's a good idea to ask your lender what would happen to your rate should interest rates fall. You can check for current rates at home mortgage loans online before you decide what mortgage to go with.

When you're doing your sums, think beyond the mortgage

For most people the mortgage calculation is a simple one: here's the repayments, can we afford them? However, there are other things to think about too. There's stamp duty, council tax and all the costs of moving home, and that's before you start redecorating your new abode. Budget carefully!

When you move house, you'll probably make a simple mortgage calculation: can I afford the repayments? If you're canny, you'll also work out whether you'd struggle should interest rates rise. However there are other factors you should take into account when you do your mortgage calculation; if you don't, you could get a nasty surprise.