Whatsapp logo.Reuters

Although the voice calling feature of Whatsapp has already been rolled out for iOS, Android and Blackberry, Windows phone users are still holding their patience to experience the feature. The voice calling ability allows users to call any contact from their Whatsapp friend list via VOIP, hence the telecom carrier won't charge for the call.

UberGizmo has spotted the voice calling feature has already been rolled out in a beta edition and only users who are into Whatsapp's Beta testing program can experience it. 

The feature is expected to be available in the upcoming final build of the Windows phone app, which will arrive soon. However, Whatsapp hasn't officially confirmed about the rollout yet.

The voice calling feature of Whatsapp debuted with the Android version of the app and was later rolled out for iOS and BlackBerry platforms. There was a lot of buzz around the feature when the service was launched, as users thought they might be able to call for hours without paying a single penny.

But you should remember there is no 'free lunch' anywhere. An earlier Android Pit research found out Whatsapp consumes almost 1.3MB of data in 60 seconds. The research also explained data consumption may vary, with an average consumption of 960KB. This means 16 hours and 45 minutes of Whatsapp calling will consume 1 GB of data.

In India, the average tariff for 1GB 3G data costs between Rs 200 and Rs 250. So, a Whatsapp call for a minute would cost around 20 paise, while traditional call charges hover around 30 to 50 paise per minute.

Again, the person receiving the call consumes an equal amount of data. In contrast, incoming call charges were withdrawn several years ago and you don't need to spend a penny unless your phone is on roaming.

Moreover, the real life experience with Whatsapp is a tad annoying too, especially in countries like India where Internet penetration rate is low and keeps fluctuating after every meter you travel. Whatsapp call service also has a delay and you would rarely see any person using the feature for this very reason.

Moreover, Whatsapp is not the first social messenger to provide this service. Apps like Line and Viber have been offering the same for long. Recently, Line launched a new service naming Popcorn Buzz which allows you to talk to 200 peoples at a time for free.