1. Test the data your calls use
Swipe into Control Center and turn Wi-Fi off, then run the test above — that tests your carrier's data, which FaceTime, Teams, Zoom and business calling apps use away from Wi-Fi. Turn Wi-Fi back on and run it again to test what Wi-Fi Calling uses indoors.
2. Grade your signal
iPhone settings that affect calls
| Task | Where |
|---|---|
| Turn on Wi-Fi Calling | Settings → Cellular → Wi-Fi Calling → turn on Wi-Fi Calling on This iPhone → Enable (Apple) |
| Open Field Test Mode (real signal numbers) | Phone app → dial *3001#12345#* → Call |
| Choose LTE / 5G for voice | Settings → Cellular → Cellular Data Options → Voice & Data |
| Reset network settings (last resort) | Settings → General → Transfer or Reset iPhone → Reset → Reset Network Settings. This erases saved Wi-Fi passwords. |
| Show your IMEI | Dial *#06# |
Menu names can change between iOS versions. Field Test Mode's layout differs between iOS versions and modem types.
3. Hear a real call
Call the free test line 804-222-1111. Press 3 for live voice echo or 4 for record-and-playback. Try it on the handset, on speaker and with AirPods to see whether an accessory is the problem.
Common iPhone call fixes
- Restart the iPhone.
- Install iOS and carrier settings updates (Settings → General → About shows a carrier update prompt when one exists).
- Turn on Wi-Fi Calling for weak indoor signal.
- Test without Bluetooth — car kits and earbuds cause many complaints.
- Clean the microphone and speaker openings, and remove cases that cover them.
- Reset Network Settings only after the steps above, since it erases saved Wi-Fi networks.
Frequently asked questions
How do I test call quality on my iPhone?
Open this page on the iPhone and run the test with Wi-Fi off and then on. Dial *3001#12345#* to see real signal numbers and enter them in the signal grader. Then call the free test line 804-222-1111 and use the echo or record-and-playback option to hear how a call actually sounds.
How do I see my real signal strength on an iPhone?
Open the Phone app, dial *3001#12345#* and press Call to open Field Test Mode. Look for RSRP, RSRQ and SINR for the serving cell. On LTE and 5G, RSRP of −80 dBm or higher is excellent and −100 dBm or lower is poor.
How do I turn on Wi-Fi Calling on iPhone?
Apple's steps: open Settings, tap Cellular, tap Wi-Fi Calling, turn on Wi-Fi Calling on This iPhone, then tap Enable. You might need to enter or confirm an address for emergency services. Your carrier must support it.
Why do calls sound bad on my iPhone?
Usually weak or noisy signal, a poor Wi-Fi connection during Wi-Fi Calling, a Bluetooth accessory, or a blocked microphone. Test with Bluetooth off, on speaker and on the handset, and compare results on cellular versus Wi-Fi.
Should I reset network settings to fix iPhone calls?
Only after restarting, updating and testing Wi-Fi Calling. Reset Network Settings (Settings, General, Transfer or Reset iPhone, Reset) clears saved Wi-Fi networks and passwords and cellular network settings, which can fix a bad configuration but won't improve weak coverage.
Why do my iPhone calls drop inside buildings?
Metal, concrete, brick and low-E glass block cellular signals. Wi-Fi Calling, a business softphone app on Wi-Fi, or an FCC-certified signal booster registered with your carrier are the standard fixes.
Sources & references
- Apple Support — Make a call with Wi-Fi Calling
- FCC — Signal boosters consumer guide
- TestCall.com — 804-222-1111 test number
Written by Eric · Reviewed November 2026