Apple iPhones require users to have both a cellular talk plan, usually sold a a fixed number or as unlimited talk minutes, and a data plan. Some data plans are unlimited, while some have fixed amounts of data. Your phone uses data any time you send or receive information other than phone calls or standard text messages. This includes sending and receiving e-mails, viewing Web pages and using any app that sends or receives information including map and GPS apps.
Determining Data Usage
iPhone users can view data usage by clicking on the "Settings" icon on their iPhone. From there, select "General" and then "Usage." Under the Cellular Network Data you will see the amount of date sent and received. Add those two numbers together to determine total usage. It's important to note the "Last Reset" number found under the Cellular Network Data section. The data usage number includes everything after that reset date. Many cellular providers also provide data usage numbers on your bill or in your online account.
Estimate Data Needs
AT&T offers an interactive online data calculator to estimate how much data you will use in a given month. Use the sliders to rate your activity in a given day or month and the calculator will give you a total. It tracks things like number of e-mails sent and received, number of e-mail attachments sent and received, number of apps downloaded and how much time you spend streaming audio and video.
If you are trying to conserve data, set your iPhone to connect to a wireless network whenever you can. Any data usage that happens while connected to a Wi-Fi network will not count against your cellular data plan.
Conserve Data with Settings
You can also conserve data by turning off some settings in your iPhone. This keeps your phone from automatically connecting when you may not want it to. Select "Notifications" from the "Settings" section and turn all settings off. This means apps with built-in notification options will not notify you when activity happens such as when new posts to your Facebok wall or replies to your Twitter feed are posted. Turning off the locations feature will also keep your iPhone from sending your location to various applications, thus saving data. To do so, click the "Settings" button and then select "General" and "Location Services" and turn the settings to "Off."