ANALYSIS: How much data do you need for iPhone 3G?

Before we delve into that discussion we need to look at who the ‘average’ iPhone 3G user is. In some cases with iPhone 3Gs costing customers $0 upfront the range of ‘average’ will be large. Let’s take a few different scenarios:

I’ve been using the first generation iPhone since July last year. I’m a Virgin mobile customer and pay $10 per month for 300MB. I have an IMAP email account setup on my iPhone and I have it set to check email every 15 minutes. On average I get around 40 emails per day. I also surf on my iPhone extensively (but normally to iPhone optimised sites like Google Reader for iPhone) – whenever I’m not near my computer. I check share prices and have recently installed an IM client too. In the twelve months I’ve had my iPhone the most GPRS data I’ve used is around 130MB. But at home I’ve got my iPhone connected on my WiFi network and during the day I’ve also got access to WiFi. I consider myself a ‘heavy’ data user.

My friend on the other-hand works as a doctor in a local hospital. He’s currently on a $49 Optus capped plan and checks his email and surfs occasionally. He told me that last month he only used 1.5MB but other times has used 10 or 15MB per month. He has access to a computer at work so prefers to surf and check email on that.

I think it’s safe to assume that most iPhone 3G customers will have access to broadband Internet at least at home and likely at work. This means that surfing/checking email on the iPhone will be limited to times they are ‘out and about’ travelling to and from work etc.

To determine what 100MB of data (the amount that Optus provide on their base $19 plan) gets you I’ve made the following assumptions:
Average email size is 15KB
Average complete webpage is 1MB
Average ‘iPhone’ optimised webpage is 20KB
Average size of iPhone Apps is 5MB
A month has 30 days

So here’s what you ‘do’ with a the 100MB of data that Optus are providing on their $19 plan?
- 6000 emails per month or 220 per day
- 100 web pages per month or 3.4 per day
- 5000 iPhone optimised web pages per month or 166 per day
- 20 iPhone Apps per month or less than 1 per day

Obviously usage will be a combination of all three but you’ll quickly realise that 100MB will go along way for the average consumer. I’d also anticipate that on average people will select a $49 plan which includes 250MB of data which based on the same set of assumptions gets you the following:
- 16600 emails per month or 555 per day
- 250 web pages per month or 8.3 per day
- 12500 iPhone optimised web pages per month 416 per day.
- 50 iPhone Apps per month or less than 1.6 per day

No doubt there will be users that need more than 250MB — especially people that watch a lot of YouTube videos streamed over the mobile network — however I’d anticipate that very few users will actually be able to use more than 250MB of data per month. While iPhone 3G offers a superb mobile experience it’s still no substitute for a full computer experience. However it’s also worth remembering that carriers will charge you blind if you exceed your data caps so monitoring your data usage over the first month is worthwhile.

iPhone 3G has a built-in usage meter (found in settings->usage) that tells you 3G/EDGE data but that of course isn’t the definitive measurement. It’s what the carrier measures on the network-side that they’ll bill you on so it’s important to check your usage with the carrier.

So far Optus has told APC that  customers will be able to view their data usage via the ‘MyUsage’ section in the ‘MyAccount’ section on the Optus website. Prepaid customers (only) will be able to SMS “balance” to 9999 to get a reading on their prepaid data balance. We haven’t yet heard from Vodafone or Telstra on how their customers will be able to keep tabs on their iPhone data usage.