If you want to buy a home, then choosing the right mortgage is one of the most important decisions you'll have to make.

Owning your home is nearly always cheaper than renting, but there are plenty of things that can affect how much it costs in the long run. We've put together this guide to help you make the right decision.

Choose an option below to find out what you want to know.

Saving for a deposit

Finding a mortgage lender

How much can I borrow?

Which type of mortgage should I choose?

Things to watch out for

Saving for a deposit

Before you can get a mortgage, you will need to have a reasonable sum of money to put down as a deposit. These days, lenders usually require at least 10%-15% of the property's value up front, but for the very best deals you'll need at least 25%.

For example, if you want to buy a house worth £120,000, you'd need £12,000 to secure a mortgage deal that needs a 10% deposit, or £30,000 if the required deposit is 25%.

You can work out the required deposit by asking for the 'LTV' (loan-to-value). The deposit you need is 100% minus the LTV% - so if the LTV is 85%, you need a 15% deposit or higher; if the LTV is 70%, you need a minimum 30% deposit, and so on.

Finding a mortgage lender

Mortgages are offered by banks and building societies, as well as a few specialist mortgage lenders. You can compare deals and apply online, or if you prefer to talk to someone it may be worth talking to a broker or an independent mortgage adviser (either over the phone or face-to-face).

Mortgages are complicated, so even if you plan on finding a deal online it can be a good idea to discuss your options with a broker or adviser beforehand.

Interest rates

When looking at mortgage deals, you'll notice they all have their own interest rate. This is the amount mortgage lenders charge on top of the amount you borrow. The higher the interest rate, the bigger your mortgage payments will be, and the more you'll pay in the long run.

How much can I borrow?

This varies from lender to lender. As a rule of thumb, you can expect to borrow around four times your annual salary (so if you earn £25,000 a year, you could borrow around £100,000). This includes your partner's income if it's a joint application.

However, all mortgage lenders are different, and some may lend more than others. They also look at overall affordability when considering how much to offer you, taking into account your other essential living costs.

And remember: you shouldn't necessarily borrow as much as you can. The more you borrow, the more you'll have to pay each month. It's always best to settle for something you can comfortably afford.

You can calculate what your mortgage payments could be using our mortgage calculator .

Which type of mortgage should I choose?

There are two main types of mortgage: variable-rate and fixed-rate. Which you should choose depends on how much risk you are willing to take.

Variable-rate mortgage (includes tracker mortgages

If you want to pay less now and you're willing to risk your payments going up in the future, a variable-rate mortgage is probably the best option. A common type of variable-rate mortgage is a tracker mortgage.

Monthly payments usually start out lower than they would on a fixed-rate deal, but there is a chance they could increase over time (although they could also fall).

Variable-rate mortgage payments are unlikely to rise very sharply, but there are no guarantees. Only choose a variable rate if you're sure you could afford an increase in your monthly payments.

Fixed-rate mortgage

If you prefer to know exactly how much you'll be paying each month, choose a fixed-rate mortgage. You'll usually pay a bit more to begin with than you would on a tracker deal, but your payments will be fixed for an agreed period (usually at least two years).

The longer the 'fix', the longer your payments will stay the same - but your interest rate is likely to be higher. Some fixed-rate deals last 3 to 5 years, and some can even last for the entire duration of the mortgage.

Things to watch out for

• A mortgage is a secured debt. This basically means that if you're unable to pay it back, your lender can repossess and sell your home to get back what they are owed.

• A mortgage is a legal contract, so there will be some legal fees to pay. Some mortgage lenders can deal with this for you, but it may be cheaper to go to a solicitor yourself and ask them to do it.

The legal fees can sometimes add thousands of pounds to your house purchase. If you haven't saved up for this, you could consider putting some of your deposit towards it instead.

• If your house value falls so much that it is worth less than the mortgage, you will still have to repay the difference. This is known as being in 'negative equity'.

This is why it's recommended to put down a decent deposit. Any fall in your home's value counts against your deposit, so the more you have saved, the better protected you will be.

• Mortgage rates are currently at record lows, so it's unlikely they will fall much in the near future. If you choose a tracker or variable-rate mortgage, be prepared for your interest rate to change in the future.