Mobile computing with smartphones and tablets frees you to access news, weather, sports and social updates from just about anywhere. This convenience comes with a price, though -- the apps and services on mobile devices use data, often served up through a cellular network. Most cell carriers impose caps on how much data may be consumed in a 30-day billing cycle. Some all-you-can-eat plans still exist, but many consumers have hard limits that, when exceeded, can result in overage charges or significantly reduced Internet speeds. Avoid the hassle of blowing your top by keeping track of where you are in the billing cycle.
Use the Device
The four major smartphone platforms -- Android, BlackBerry, iOS and Windows Phone -- differ in their ability to track and report mobile data usage.
Android devices running Android 4.0 (Ice Cream Sandwich) or later include a sophisticated data usage meter into the system settings menu. This counter records the amount of data passing through the device, but it may not perfectly match the totals calculated by your mobile carrier.
Apple's iOS for the iPhone and iPad and BlackBerry devices do not have robust built-in monitoring tools. IPhones, for example, will track a simple number that lacks context against a billing cycle. Windows Phone 7 also lacks internal meters, but Microsoft has confirmed that Windows Phone 8 -- scheduled to roll out in October 2012 -- will include a comprehensive data-usage monitor within the operating system.Use Your Carrier
Each of the four largest telecoms in the United States -- Verizon, AT&T, Sprint and T-Mobile -- show how much data a customer uses in the billing cycle. T-Mobile, for example, includes a graphical progress bar on its account-management page indicating how many megabytes of data have been consumed and how many remain; this graph is independent of the phone, so it'll work just as well measuring an Android phone as a BlackBerry.
Some carriers offer apps for some mobile platforms, too. Verizon provides the My Verizon app for Android and iOS; it provides real-time statistics about data, voice and text messaging against any monthly limits in your plan. T-Mobile offers the MyAccount app for Android and Windows Phone 7 that provides similar functionality, as does AT&T with its MyAT&T app for Android and iOS.
Sprint customers must log in to their account page using a Web browser; this carrier doesn't offer custom account apps.Use an App
Every mobile platform includes an app store containing several different third-party apps to track usage. Although each app differs in what it tracks, they all monitor the device's radios to record the amount of inbound and outbound data through the cell network. Some even log calls, text messages or Wi-Fi usage.
Android users could check out 3G Watchdog or My Data Manager, both available through Google Play. The BlackBerry App World includes Network Traffic Control. The Apple App Store includes Data Usage. Windows Phone 7 does not include third-party apps -- only apps released by a cell carrier.Limit Roaming
If you're close to your data cap, or you frequently operate on a roaming network, don't forget that your carrier's current meter may not be accurate. T-Mobile advises that roaming data usage can take up to 30 days to be reported and added to your account, putting you at jeopardy for overage charges or service throttling. Because your carrier's meter is what governs your bill, you'll need to keep track of data usage off-network or even disable data roaming on your device.
If you do approach your cap, try offloading your data to Wi-Fi. Wi-Fi usage never counts towards a cell-data cap.