Most of us are probably aware that we spend more on our mobile phone tariff than we really need to; in fact a study of UK mobile customers found that 82% of us are on plans with minutes we don't use. That means we could save as much as £197 a year by switching to a cheaper tariff. Who really wants to spend hours trying to work out if a different deal would be cheaper though?

Luckily you don't have to. New service BillMonitor will do it for you! See how it works over the jump.

BillMonitor is a free service which helps you work out if and how you can save money on your mobile phone bills. It does this by calculating how much you actually use your phone and for what specifically (international calls, texts etc). Then it takes this information and applies it to thousands of different tariffs on the market to work out whether one of those offers you a better deal.

You can calculate your current usage on BillMonitor in two ways. You can either manually estimate how many minutes and texts you use each month as well as other information like if you plan to make international calls for instance. Or, you can use the even better 'analyse your bill' option. To use this option you have to give BillMonitor access to your mobile bills. This allows the site to calculate how you use your phone each month - it can analyse exactly how much you talk, text, call abroad, transfer data and so on. In each case the site then uses the data you provide against a huge selection of phone packages to let you know whether there's a better deal for you out there.

To use the 'analyse your bill' feature, you need to be registered for online billing with your phone company first. This is really simple to do if you haven't already got it set up – there should be a section on your phone network's website allowing you to do this. Then, once you've entered your details, the feature will automatically analyse your bills. It shows you exactly how much you use your phone, what for and how much it costs you.

Once it has searched through the multitude of other phone tariffs, it lists the results in order of price. It also displays what's included in the deal and the length of the contract. Plus you can filter the results by price, network, contract length or handset.

'Safe' Plans

A particularly good feature of the site is that it errs on the side of caution when recommending tariffs. In your results you will find one tariff is labelled as being the 'Safest Plan'. Basically, BillMonitor will suggest plans that won't break the bank if you go over your usual level of phone usage one month. I think this is far better than recommending deals that might appear slightly cheaper, but actually cost a fortune if you go over your allowance.

Drawbacks

• At the moment BillMonitor can only make these calculations for pay monthly customers; there is no facility for pay-as-you-go.
• It doesn't yet recognise all providers - Tesco mobile tariffs are unfortunately not included as yet.
• You can't search the results for deals which include particular types of phone, or handsets with particular features.

Despite all that, it does have the potential to save you considerable amounts of money, so is definitely still worth a look.