The short answer
Wi-Fi calling routes calls over your broadband instead of the mobile network, which solves poor indoor signal completely. Enable it in the phone’s mobile network settings, check your carrier supports it, and set the emergency address, which is a requirement rather than an optional step.
Mobile signal indoors is a building materials problem. Modern insulation, foil-backed plasterboard, thick stone walls and metallised glass all block the frequencies that carry calls. No amount of network investment changes what happens inside your house. Wi-Fi calling sidesteps the issue by carrying the call over your broadband and handing it to the carrier’s network at the other end.
Turning it on
Check your carrier supports it
Nearly all major carriers do, and some prepaid and virtual operators do not. A quick check on the carrier’s site saves confusion.
Find the setting
On iPhone, Settings, then Apps or Phone, then Wi-Fi Calling. On Android, Settings, Network and internet, SIMs, then your carrier, then Wi-Fi calling. Manufacturer skins move it, so searching the settings for the phrase is quickest.
Enable it and accept the terms
You will be asked to confirm that emergency calls may be handled differently.
Set the emergency address
This is the address given to emergency services if you call from Wi-Fi, since the network cannot locate you by tower. Keep it current if you move.
Choose the calling preference
Most phones let you prefer Wi-Fi or prefer mobile. Prefer Wi-Fi if your indoor signal is poor, which is presumably why you are enabling it.
Check the status indicator
The status bar usually shows a Wi-Fi calling label or the carrier name with a Wi-Fi symbol when it is active.
Wi-Fi calling and VoLTE are related and different. VoLTE carries calls over the 4G data network rather than the old voice network, which improves quality and lets data continue during a call. Both are worth enabling, and they usually sit next to each other in the same settings screen.
What changes when you use it
- Calls use very little bandwidth, around 100kbps, so it works on almost any connection and will not affect streaming.
- Calls are usually free in the same way as normal calls, billed against your plan rather than as data. Check international rules, since calling home from abroad over Wi-Fi is often treated as a domestic call, which can be a significant saving.
- Handover between Wi-Fi and mobile is supported by most carriers, so a call can continue as you leave the house. It is not universal, and where it is not supported the call drops at the door.
- Texts go over Wi-Fi too, which is often the more useful part in a house with no signal.
- Emergency calls may be routed by your registered address rather than your actual location, which is why keeping it accurate matters.
When it does not work well
- Poor Wi-Fi. Wi-Fi calling on a marginal connection is worse than a marginal mobile signal, because packet loss produces robotic audio and dropped calls. If your Wi-Fi is weak where you make calls, fix the Wi-Fi first.
- Congested broadband. Calls are small but latency-sensitive. A household saturating its upload with backups or video calls can degrade voice quality, and quality-of-service settings on the router help.
- Restrictive networks. Some corporate and public networks block the protocols Wi-Fi calling uses. It will simply fail to register rather than explaining why.
- Double NAT. Two routers in series can prevent registration. Putting the ISP box in bridge mode resolves it.
- VPN active. A VPN on the phone often breaks Wi-Fi calling registration. Excluding it or disabling the VPN at home fixes it.
If Wi-Fi calling refuses to activate, restart the phone with Wi-Fi on and mobile data off, then re-enable the setting. Registration happens with the carrier at activation and sometimes needs a clean attempt. A carrier settings update, which is separate from a system update, is the other common requirement.
Alternatives if it is unavailable
If your carrier does not offer it, or your phone does not support it:
- A femtocell or signal booster from the carrier creates a small mobile cell in your home using your broadband. Carriers sometimes supply these free to customers with documented poor coverage.
- A passive signal repeater with an external antenna can work where there is usable signal outside the building. Check the legality in your country, since unauthorised repeaters are prohibited in many places.
- Calling apps over the internet work for people who also use them, and do not solve the problem of ordinary calls to ordinary numbers.
- Changing carrier is sometimes the honest answer, since coverage varies enormously street by street. Ask neighbours which network works in their house.
Does Wi-Fi calling cost extra?
Usually not. Calls are billed against your normal allowance. Calling your home country from abroad over Wi-Fi is often charged as a domestic call, which can save a great deal, and it is worth confirming with your carrier.
Does it use a lot of data?
No, around 1MB per minute. It will not affect your broadband usage meaningfully, and it will not consume your mobile data allowance since it uses Wi-Fi.
Will the call drop when I leave the house?
On most carriers the call hands over to the mobile network automatically. Where handover is unsupported, the call drops as you leave Wi-Fi range, which is worth testing once.
Can I call emergency services over Wi-Fi calling?
Yes, and the location may be based on your registered address rather than your actual position, which is why keeping that address accurate matters. Where mobile signal exists, phones normally prefer the mobile network for emergency calls.
Why does Wi-Fi calling keep turning itself off?
Usually a registration failure with the carrier, often caused by a VPN, a restrictive network or double NAT. Restart with mobile data off, check for a carrier settings update, and disable any VPN as a test.
The summary
Turn it on in the mobile network settings, set the emergency address, and prefer Wi-Fi if your indoor signal is the problem. Make sure the Wi-Fi where you actually make calls is strong, because a weak connection is worse than no Wi-Fi calling at all. And if it refuses to register, look at VPNs, double NAT and carrier settings updates before anything else.
