What wifi calling is and when to use it

Wifi calling lets a phone make or receive voice calls over a wifi network, and your carrier must offer the feature. You turn it on in your settings, and your phone can then route calls over a wifi network such as your home router when cell signal is weak.

How a call travels over wifi instead of a cell tower

Smartphones normally act like two-way radios. They send invisible waves through the air to reach a local cell tower. The tower catches the radio waves and sends them along wires to your carrier. Your carrier then connects you to your friend.

This system works perfectly when you stand outside in open space. Things change when you walk inside a building. The radio waves hit the exterior walls and lose their strength. Brick, stone and concrete can weaken the cellular signal.

Metal roofs, tinted windows and some insulation can also weaken the signal. By the time the waves reach your phone in the living room, they can be very weak. Your calls drop, or the person on the other end sounds like they are underwater.

Wifi calling changes the path your voice takes. Your phone sends the call over wifi to the wireless router in your house instead of to a distant cell tower. The router grabs your voice data and pushes it through your home internet connection.

The data then travels through your internet provider's network. Most homes need both a modem and a router to connect to the internet provider. The provider receives the data and hands it off to your cell carrier.

The carrier routes the call normally from there. The person you call usually does not notice a difference. They answer their phone just like always.

When wifi calling helps most

This setting solves the specific problem of dead zones. You use it when you have a weak cell signal but a solid internet connection. Some homes sit in pockets of land where cell towers cannot reach well.

Hills, tall trees and large buildings block the tower from seeing your house. You might have full bars of service at the grocery store but zero bars in your own kitchen.

Basements cause the same trouble for phone calls. The dirt and concrete surrounding a basement wall can block cell signals. If you set up a home office underground, you might miss incoming calls.

An internet connection bypasses the local terrain and the architecture. You rely entirely on your broadband router to carry the conversation. A strong wifi connection usually helps calls sound clear.

You stop pressing your face against the window glass to hear the other person. The setting also helps in large concrete apartment buildings. You might live high above the street, but the heavy floors above and below you can hurt the cellular reception. The router inside your apartment usually provides a strong connection nearby.

How to turn it on in your phone settings

Your phone hides this switch in the main settings menu. You activate the setting by tapping through the menus on your device. On an iPhone, the steps look like this:

1. Open the settings app on your home screen.
2. Tap the cellular menu option.
3. Tap wifi calling. If you have more than one line, choose the line first.
4. Turn on wifi calling on this iPhone, then tap enable.

Android menus differ by phone maker and carrier, so the wording may vary, but the path is often similar:

1. Open the settings app.
2. Tap the connections or network menu.
3. Tap the mobile network section.
4. Slide the wifi calling toggle to turn it on.

The phone takes a moment to communicate with your carrier. When you turn on wifi calling you might need to enter or confirm your address for emergency services. A screen may ask for your street address, city, state and zip code. You type this in and save it.

Apple says a Wi-Fi label shows in the status bar when wifi calling is available.

Why your emergency address matters for 911

The address you register for wifi calling matters because a wifi network usually cannot tell the 911 system where you are. Apple says your device's location may also be used to help responders.

That is why an outdated address can cause trouble with a wifi 911 call.

Apple says an iPhone uses cellular service for emergency calls when it is available, and may use wifi calling when it is not. When the phone uses wifi calling to reach 911, the call may carry the registered address you typed into the settings menu.

You must keep this address accurate. An FCC report to Congress dated March 23, 2021 says wifi calling users typically must provide a registered address and update it by hand as their location changes.

If you move to a new house, enter the new address. When you stay somewhere else for a while, update it there as well.

An outdated address can cause problems in an emergency. The same FCC report says that if a caller is not at the registered location, a wifi 911 call may not reach the closest 911 center or may be misrouted.

A call that lands at the wrong 911 center can lose time, so keep the address current.

Check your carrier on minutes and data

You might wonder if routing your calls through the internet changes your monthly phone bill. The answer depends on your carrier, so check its website or support line.

Ask whether wifi calls count against your plan minutes. The call itself travels over your home broadband connection to reach the carrier.

Ask whether wifi calls count toward any cellular data allowance. They do use some of your home internet connection.

Ask your carrier about international calls from the United States, since charges can differ.

Ask how calls are billed when you travel abroad, because rules vary between phone companies. You should check your carrier website before traveling to avoid surprise fees.

Fixing calls that drop when you leave the house

A phone can handle the transition between internet and cellular signals poorly. You might start a conversation in your kitchen where the internet signal is strong. You then grab your keys and walk out the front door to the driveway.

A phone may hold onto the home wifi connection until it is very weak, and the call can drop before it switches.

The conversation can cut out and the call might drop. You might be able to avoid this by managing the handoff yourself.

If a call tends to drop when you leave, you can try turning off wifi before you walk outside so the phone moves to the cell network. This only helps if you have cell signal where you are standing.

You can also wait to start the call until you are in the car, away from the house, where the phone is more likely to use the cell network.

Sometimes the problem happens entirely inside the house. You walk from the living room to a back bedroom and the call fails. This may indicate a dead spot in your home internet coverage.

Read if wifi extenders work to see if pushing the signal deeper into the house helps. A weak wifi signal can drop a phone call just like a weak cell signal.