The icons in the status bar at the top of the screen give information about iPhone:

Status icon

What it means

cellular signal strength status icon (five dots)

Cell signal

You’re in range of the cellular network and can make and receive calls. If there’s no signal, “No service” appears.

the AirPlane mode status icon

Airplane mode

Airplane mode is on—you can’t make phone calls, and other wireless functions may be disabled. See Travel with iPhone.

the LTE status icon

LTE

Your carrier’s LTE network is available, and iPhone can connect to the Internet over that network. (iPhone 5 or later. Not available in all areas.) See Cellular settings.

the 4G status icon

UMTS

Your carrier’s 4G UMTS (GSM) or LTE network (depending on carrier) is available, and iPhone can connect to the Internet over that network. (iPhone 4s or later. Not available in all areas.) See Cellular settings.

the 3G status icon

UMTS/EV-DO

Your carrier’s 3G UMTS (GSM) or EV-DO (CDMA) network is available, and iPhone can connect to the Internet over that network. See Cellular settings.

the EDGE status icon (an "E")

EDGE

Your carrier’s EDGE (GSM) network is available, and iPhone can connect to the Internet over that network. See Cellular settings.

the GPRS status icon

GPRS/1xRTT

Your carrier’s GPRS (GSM) or 1xRTT (CDMA) network is available, and iPhone can connect to the Internet over that network. See Cellular settings.

the Wi-Fi status icon

Wi-Fi

iPhone is connected to the Internet over a Wi-Fi network. See Connect to Wi-Fi.

the Do Not Disturb status icon

Do Not Disturb

“Do Not Disturb” is turned on. See Do Not Disturb.

the Personal Hotspot status icon

Personal Hotspot

iPhone is providing a Personal Hotspot for another device. See Personal Hotspot.

the syncing status icon

Syncing

iPhone is syncing with iTunes.

the network activity status icon

Network activity

Shows that there’s network activity. Some third-party apps may also use it to show an active process.

the call forwarding status icon

Call Forwarding

Call Forwarding is set up. See Call forwarding, call waiting, and caller ID.

the VPN status icon

VPN

You’re connected to a network using VPN. See Network access.

the TTY status icon

TTY

iPhone is set to work with a TTY machine. See TTY support.

the portrait orientation lock status icon

Portrait orientation lock

The iPhone screen is locked in portrait orientation. See Change the screen orientation.

the alarm status icon

Alarm

An alarm is set. See Alarms and timers.

the Location Services status icon

Location Services

An item is using Location Services. See Privacy.

the Bluetooth status icon

Bluetooth®

Blue or white icon:  Bluetooth is on and paired with a device.

Gray icon:  Bluetooth is on. If iPhone is paired with a device, the device may be out of range or turned off.

No icon:  Bluetooth is turned off.

See Bluetooth devices.

the Bluetooth battery status icon

Bluetooth battery

Shows the battery level of a paired Bluetooth device.

the battery status icon

Battery

Shows the iPhone battery level or charging status. See Charge and monitor the battery.