How BillMonitor Works

Scientific Analysis

Finding the right mobile tariff is confusing because of the huge number of ever-changing deals, tariffs and addons. To find the best mobile deal for you BillMonitor compares them all — for the way you use your mobile phone.

Finding the tariffs where your bill costs less

It’s all based on working out how much your mobile bill will cost on all of the 8,903,546 deals that BillMonitor compares. We run through every call, text and byte of data on your bill, working out the cost on each tariff. Taking into account all the little details like free minutes, off-peak calling and charge limits, we can then show you the 12 tariffs that could save you the most. But there’s a little more to it than that…

Making sure you don’t get stung

Next month you might make a few more calls than usual; if we recommended a plan with just enough free minutes to cover your recent usage you might get stung with a huge bill. Bad idea! This is where the statistics developed by BillMonitor’s science team come into play. We vary your last 3 months bill in a precise way – adding a little here, removing a little there and seeing if the cost changes. If the cost sky-rockets for a little more usage on a particular tariff that tariff gets a lower position in the results (and rightly so.) The final cost we display is the average for all the different versions of your bill.

(We should point out that this sometimes leads to curious-looking-but-correct results. For example: if you put in 200 minutes as your estimated usage and a tariff has 200 free minutes there might be some non-free calls. This is because one or more versions of the bill used more than 200 minutes.)

Showing you the results

As well as the cheapest tariffs, our results always include at least one result from each operator. This way you can see the how competitive they all are and get an overview of the market.

The Best Results Come From Analysing Your Bills

BillMonitor works best when it can see the exact way you use your mobile phone from your online bill. If you tell us your usage instead we make a virtual bill for you that then goes though the same process.

When we create a virtual bill for you we make a few assumptions about how you might use your phone. These are based on how most people use their mobile.

We assume:

  • The same amount of peak and off-peak calls will be made.
  • 32% of your calls will be to landlines, the rest to other mobiles.
  • Mobile calls will be made to each network in proportion to their relative subscriber numbers.
  • Calls made have a varying length, with an average length that rises as the amount of minutes used per month rises. For 500 minutes per month the average call length is about 2 and a half minutes.
  • When roaming, half of calls will be made to the country you’re in, the other half back to the UK.
  • When you pick a region for international or roaming, we pick 5 popular countries in that region, and spread the usage evenly among them. We’ve taken care to pick countries that represent the costs of the region fairly so you won’t get surprised.
  • For roaming usage we multiply the number of trips specified by the minutes and texts per trip to give an annual usage level, with usage spread evenly through the year.

If you’re not happy with these assumptions, submitting your bill to our automatic bill assessment service is the best way to get accurate recommendations.

Confused? Curious? Drop us a note at feedback@billmonitor.com