How to check Wi-Fi signal strength on iPhone
Your iPhone shows three Wi-Fi bars and nothing else. Here's what you can actually measure, and which numbers matter.
In this guide
On a Mac or a laptop you can usually see a precise Wi-Fi signal value. On an iPhone, you get three curved bars. That's not an oversight: iOS deliberately doesn't expose the raw signal value to users or to App Store apps. You still have good options, as long as you know what each one measures.
Method 1: the Wi-Fi bars
The Wi-Fi icon in the status bar and in Settings → Wi-Fi shows up to three bars.
- Three bars: good signal.
- Two bars: usable, but you may be near the edge of reliable coverage.
- One bar: weak. Expect buffering and dropped calls.
The bars are a rough guide. They're fine for spotting a dead zone, but they can't tell you whether a room is "just okay" or "about to fail", and two phones can show different bars in the same spot.
Method 2: see the dBm value with Apple's AirPort Utility
Apple's free AirPort Utility app has long included a hidden Wi-Fi scanner that shows the real signal value:
- Install AirPort Utility from the App Store.
- Open the iPhone Settings app, scroll down to AirPort Utility and turn on Wi-Fi Scanner.
- Open AirPort Utility and tap Wi-Fi Scan, then Scan.
- Find your network in the list. The RSSI column is the signal strength in dBm.
The scan is a snapshot of where you're standing, so you'll need to repeat it in each room and write the values down. If the app isn't available in your region, the Mac method below gives you the same numbers.
Method 3: use a Mac for precise readings
If you have a Mac, hold the Option key and click the Wi-Fi icon in the menu bar. You'll see details about the current connection, including RSSI (signal strength) and Noise. Carry the laptop from room to room and compare.
What the dBm numbers mean
Signal strength is measured in negative numbers: the closer to zero, the stronger the signal. These are common rules of thumb:
| RSSI | Quality | What works |
|---|---|---|
| −30 to −50 dBm | Excellent | Everything, including large downloads |
| −50 to −60 dBm | Very good | 4K streaming, video calls |
| −60 to −67 dBm | Good | Streaming and calls, the usual target for reliable use |
| −67 to −75 dBm | Fair to weak | Browsing works, calls and video can stutter |
| Below −75 dBm | Poor | Frequent buffering and disconnections |
Keep in mind that signal strength isn't the whole story. A strong signal on a crowded channel can still perform badly, which is why measuring how the connection actually behaves is often more useful than the dBm value alone.
Method 4: measure Wi-Fi quality room by room
For a home, the real question is rarely "what is the dBm here?". It's "which rooms have a connection that struggles?". That's easier to answer with a map than with a column of numbers.
WiFi Heatmap is built for that: you create a floor plan on your iPhone, walk through each room while the app measures how your connection responds, and get a colored map with a quality score out of 100 for every room. It doesn't show dBm, for the iOS reasons above, but it shows where the Wi-Fi fails, which is what you need to fix it. Learn more in what a Wi-Fi heatmap is.
Why a speed test isn't enough
Speed test apps are easy to run, but they measure your whole internet path to a remote server. A slow result can come from your internet plan, the provider, or a busy server, not from your Wi-Fi. If the test is slow next to the router too, your Wi-Fi coverage isn't the problem. If it's fast next to the router and slow in the bedroom, it is: see how to find Wi-Fi dead zones.
Frequently asked questions
Can an iPhone app show Wi-Fi signal in dBm?
Not with App Store apps on current iOS versions, because Apple doesn't give apps access to the raw signal value. Apple's own AirPort Utility is the exception, through its Wi-Fi Scanner option.
Why does my iPhone show full bars but the internet is slow?
The bars only reflect signal strength. Slowness can come from interference, too many devices, a slow internet plan or a problem at the provider. Test next to the router: if it's slow there too, the issue isn't coverage.
What's a good Wi-Fi signal strength?
Around −67 dBm or better is a common target for smooth video calls and streaming. Between −67 and −75 dBm things usually still work, but less reliably.
Why do two iPhones show different bars in the same room?
Different models have different antennas and radios, and a case or the way you hold the phone also matters. Always compare rooms with the same device.