This nifty database shows how apps suck up your data plan

Apps actually come at a greater cost than the price tag on the app store: drains to battery life and data plans, especially from resource-heavy programs, can ultimately be a total money suck. But a new database, assembled by mobile trade group CTIA, helps inform users about the data usage of mobile apps for iOS(s aapl) and Android (s goog), according to PC World.

Know My App is a database that archives the amount of data for apps on all platforms, but currently lists just the Top 50 Paid and Free apps. Each app is measured based on pre-defined “average” interactions. For example, Facebook’s(s fb) data measurement is based on “3 sessions of the following scenario: Posting 5 Comments, “Liking” 5 posts, viewing one embedded video, viewing 3 embedded photos, scroll through Timeline, 1 Check-In, Uploading 1 photo.” Average usage for Netflix, on the other hand, is defined as “2 sessions of the following scenario: Search for TV show, Watch TV show (for 9 minutes), Add TV show to favorites, pause video, turn on captions, rotate device, adjust volume, rewind/fast forward, view category.”

Of course, it’s no surprise that the impact on data is severe. In Know My App’s database, Facebook’s average data use (based on a Sprint(s s) iPhone 4S)  is 433.77MB per month — more than 20 percent of an average 2GB data plan and well over the budget 300MB plan. Netflix(s nflx) is an even bigger data vampire, pulling down more than 4GB per month. While it’s not a big deal when a device is on Wi-Fi, the data impact is enough to use up even the higher end of wireless data plans.

While it may cause a bit of sticker shock, the CTIA’s database is only a rough guideline for how much data apps can suck out of your phone. It certainly doesn’t provide a tailored experience based on each user’s behavior, like the information offered by Onavo and similar apps, so it’s hard to make tweaks and find solutions for users that want these apps on their devices. However, it does do a good job of showing users the hidden cost of apps, and goes an extra step by helping developers figure out the best way to keep their apps’ data usage low. It’s a nifty little search that may make you think twice before downloading an app.