Per MB billing: the hidden data vampire

Data inclusions are becoming the true test of value in mobile phone plans and on the surface this is easy to compare. But there is one hidden factor that deserves just as much attention, and that’s how your data use is calculated.

In Australia, there are currently three variations on the way billed data is calculated: per kilobyte (KB), per 10KB and per megabyte (MB) — where 1MB equals 1,024KB.

This determines how your telco ‘rounds up’ data usage at the end of a data session. For example, if your phone downloads an email and the data session ends after receiving 5KB of data, one telco will bill you for 5KB, another will bill you for 10KB, while a third will round up to 1MB -- more than 200x the actual data used.

Comparing the value of such tiny increments of data might sound like splitting hairs, but the fact is that over a month of usage, and hundreds of data sessions, discrepancies between per KB and per MB billing start to add up.

Big, wasted Data

Whirlpool forum member ‘Ozzapoo’ has created a data calculator to see how much data is wasted each month on data rounding. He invited Whirlpool members to enter itemised data usage from mobile bills, and then used this information to breakdown how much data they actually used and how much they were billed for.

The results from over 300 submissions is startling. On average, there was a 283MB difference between how much data was used and how much had been billed for — which is nearly one-fifth wasted from an average 1.5GB data plan.

But based on graphs created by ‘Ozzapoo’ from the data collected, there were dozens of people who had over 1GB of data deducted from their allowances that they did not use. This from a sample of just over 300 data bills.

You can try the calculator for yourself here. You just need a list of all data sessions for a month, listed in a KB format.

An example

To see this calculator in action, I grabbed a month’s usage from my current Telechoice bill and plugged them in. To make the job easier, I pasted my bill in Excel so I could isolate the data usage.

As you can see, there are a number of sessions using less than 10KB worth of data — about 180 tiny sessions in total for the month.

Luckily, because Telechoice rounds up to 10KB, I will only be billed for 1.63MB of extra data. But if my account was with a telco who billed in 1MB blocks I'd be looking at nearly 400MB of wasted data this month, thanks to all the tiny sessions that would need to be rounded up.

A lesson in sessions

The tricky part about calculating how much extra data you may pay for is determining when a data session ends. Modern smartphones attempt to create a constant single session once they are switched on, but our connection to the network is often cycled from a number of different reasons.

“There are various ways a data session can conclude. This could be related to a an email application timing out, the handset itself timing out; which is dependent on the settings determined by the manufacturer, or an idle session where our system will conclude a data session based on inactivity,” said a Vodafone spokesperson.

An Optus spokesperson explained data sessions in a very similar way, saying newer smartphones are more likely to maintain longer continuous sessions, while older phones may disconnect and reconnect to the network as needed.

'Ozzapoo' explained that the murky definition of a data session is one of the major obstacles in determining the accuracy of the data calculator.

"There seems to be almost no concrete information on this topic at the moment. Who knows, the calculator might even turn out to be irrelevant!"

Unfortunately, there is no way for phone users to make any adjustments to how their handsets interact with the network, so you are beholden to how your phone’s software design and how aggressive your network is in clearing out idle connections to make room for new users.

How your telco bills

You can usually find this information in the Critical Information Summaries (CIS) that all telcos are obliged to create for all mobile phone plans. To find the CIS for your plan, navigate to the plan page on your telco's website and look for the link.

	Per KB	Per 10KB	Per MB
	Yes	----	----
	Yes	----	----
	Yes	-----	-----
	Yes Post-paid	-----	Yes Pre-paid
	Yes	-----	-----
	Yes	-----	-----
	Yes	-----	----
	----	Yes	----
	----	----	Yes
	----	----	Yes
	Yes	----	----
	Yes	----	----
	Yes	-----	----
	Yes	----	----
	----	Yes	----
	Yes	----	----
	Yes	----	----

Joseph Hanlon

Editorial Director | X | LinkedIn

Joe Hanlon has been immersed in mobile phones, plans and the internet for over a decade, having written for publications like CNET, Techradar, Gizmodo and Lifehacker. He steers the editorial ship and makes sure that we are always serving up the most useful guides and recommendations. If you ever bump into Joe on the street, don't be afraid to ask for a phone recommendation. It's embarrassing how much he enjoys talking about this stuff. He also loves listening to podcasts, so feel free to email Joe with recommendations.

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