Got an iPhone 5 or a new smartphone with a fresh contract?  Worried about going over your data plan?  Not to worry, there’s an app for that.  Many people aren’t aware of the apps out there that will track your monthly data habits, and even alert you as you near your monthly data limit.

Don’t get caught off guard with data overages on your next carrier bill.  Here’s a list of top data counter apps for iOS and Android, along with our recommendations.

iOS Data Monitoring Apps

Data Usage  (99 cents)

This app runs in the background and periodically shows you used, remaining or predicted percentage of data consumption.  You’ll get an alert when you reach a specified data usage level, to help keep you from data overages.  You can set up monthly, weekly and daily data limits, and supports a flexible recurring billing period.  This Data Usage app also calculates ideal daily data usage percentages, and monitors both cellular and WiFi data activity.

DataMan  (99 cents)

This app monitors your data usage in real-time so you can stay well within your data plan.  It tracks your monthly data usage, including cellular (LTE/4G/3G) and Wi-Fi networks, has four levels of usage threshold alerts, and the counter rests at the end of billing cycle.  It also provides you a monthly history so you can easily see if there’s a change in your data consumption as the months progress.

Data Counter  ($1.99)

This app checks the traffic produced on GPRS, EDGE, 3G networks and WiFi, plus it has a download speed indicator.  Data Counter also allows you to set limits, and alerts you if you’re about to reach your data limit, all the while recording information about your traffic usage during the day.

Our pick for iOS:

Of the above mentioned apps, we recommend Data Usage since it covers both cellular and WiFi data usage, and allows monthly, weekly and daily limits.  Great for shared data plans as well.

Android data monitoring apps

Onavo Count | Monitor Data  (free)

This app notifies you on which of your apps hog the most data, and warns you if you are near your monthly data limit, and even your roaming limit if you are traveling.  Aside from that, you can customize settings so that data hogging apps only use WiFi, or set restrictions on your device so that when you reach your monthly limit, you can no longer connect to the internet to circumvent data overages on your monthly bill.

Plus, you’ll get predictions for when you’ll hit your data limit based on your activity.  This app has an average rating of 4.5 stars.

3G Watchdog  (free)

This is a data counter that monitors a person’s mobile internet consumption over 4G/3G/Edge/GPRS, shows a status icon (green/orange/red) in the notification bar and a detailed report page to let you know if you are nearing your limit.  Though it does have issues on some devices, like the Galaxy Tab 10.1 and 8.9, users are generally happy with the app with an average rating of 4.7 stars.

My Data Manager  (free)

This apps lets you know how much data your apps use and which of them consume the most.  It also allows you to set an alarm to let you know if you are nearing your monthly data limit, and it ensures you are using your ideal data plan and maximizes how you use your data.  This app has an average rating of 4.6 stars.

Our pick for Android:

Of the data counters mentioned above, we recommend the Onavo Count app if you’re serious about not going over your monthly data limit, since you can put restrictions on your device.  The best part about this is that Onavo tells you which apps consume the most data, and you have the option of restricting that app to only use a WiFi network.  It’s the preventative measures that count.

To learn more about how you can curb your data consumption, check out 3 Ways to Cut iPhone 5 Data Usage, Avert Overages.