Calculator: How much data does WhatsApp use and what are the costs?

WhatsApp is one of the few apps that I will gladly pay for when the beta period is over, but how much data does it use?  I have done some experimentation over this weekend and have published the results in the attached calculator.   
Click here to download the calculator: HTT’s WhatsApp Costs Calculator
Note: This is by no means a scientific experiment/calculator, I just wanted to get a feeling for how much data is being used and what charges are actually being charged by Vodacom on my prepaid, no data bundle account that charges R2 per MB.If you are on a BlackBerry then WhatsApp uses your BIS or BES service (refer to WhatsApp FAQ), so it doesn’t incur any additional data costs (as long as you are not roaming internationally).  See posting here for how to set up your phone while out of your home country: Roaming using your Blackberry and don’t want to use Data Services from the cell phone network: SOLVED

If you have a phone that can connect to WiFi routers (like your ADSL router at home) then WhatsApp will connect over that WiFi connection rather than incurring costs on your cell phone’s data bundle.  As you can see from the spreadsheet the costs for 4KB over WiFi on ADSL is 1/100th of a ZA cent.

Polling data costs:
OK, so how much are we spending when we send WhatsApp messages and how much when we’re not?
Hold on there…. how much do we spend when we’re not sending messages? – What on earth does that mean?
Well, I noticed that even when you aren’t actually sending text messages there are data packets being sent (and charged for).  I call these data costs “WhatsApp polling” overheads.  I assume that WhatsApp is communicating to their server to keep the channel open. 
It’s difficult to figure out how many polls are made per hour.  I’ve noticed sometimes up to 4 per hour – and some hours with none at all.
I’ve taken an average of 3 polls per hour, makes 72 per day, of 1,024 bytes charged at ZAR0.01 per poll: costs R21.60 per month 

Messaging data costs:
Then there are actual costs for sending messages.  The receiver will also incur data costs if they are not on BIS/BES or other cheaper data connections.

Note: cell phone network providers allow you to buy pre-paid bundles of data at a much reduced rate – beware though, it’s on a “use-it-or-lose-it” basis. Vodacom gives you until the end of the following month to use up the data. Note: that’s not a 2 month window! (unless you buy on the 1st of the month). If you buy a bundle on the 20th of April, then the data will expire at the end of the following month ie: end May in this example.

I sent some experimental messages and one specific message of precisely 100 characters to see what was actually billed by Vodacom.
I checked her mini-statement online using Vodacom’s online “Mini-Statement” – updated hourly (more or less).
BTW: @Vodacom, please allow prepaid users to see more than 1 page of their billing for free!  Unless you are really trying to keep them in the dark on the costs – the last 10 transactions is really so pre-data connections!… like ummm so 1990‘s

Note the 100 character message that I sent:
     a) row 9: WhatsApp message of 100 characters was charged ZAR0.22 by Vodacom.  I expected that to be much less than that – so I resent that message later in the day:
    b) row 3: WhatsApp message of 100 characters was charged ZAR0.01 by Vodacom – that’s more like it!  So, I tried it again – to be sure (if that’s possible)
    c) row 2: WhatsApp message of 100 characters was charged ZAR0.01 by Vodacom – OK, so now I’m sure… the first message must have included some polling “extras”.

It also seems that Vodacom round the data charges to the nearest KB (thousand bytes).

So, as you can see it’s not a scientific analysis, but I am pretty sure the SMS and call costs that I would incur if it were not for WhatsApp would be much higher than the above illustrated costs. 

Battery cost:
The “always on” way that WhatsApp communicates with its home server uses the phone’s data channel – which uses more power than if there wasn’t data communications happening.  So, expect to be charging your phone more often than before.
This is not a problem for me – but might be for some.
I guess, it’s a trade-off between how many SMSs you normally send vs how many you don’t now that you have WhatsApp.  For me, it’s a no-brainer! 

WhatsApp program cost:
You can use the app for free for 12 months, then you need to pay per year.
Download by clicking these links:
Nokia and BlackBerry and Android: $1.99 USD/year (~R13.50);
iPhone $0.99/year (~R6.75); 

The latest versions of WhatsApp allow sending of group messages and photos and voice notes – note: these are larger in size than “plain” text instant messages, so costs will go up due to higher data costs – but it’s still cheaper than sending MMS messages (MultiMedia messages).


WhatsApp, you are great – thanks… and I will definitely be purchasing an annual license for my phones!