sudo wdutil infoPrint current Wi-Fi details: signal (RSSI), noise, channel, transmit rate and more.
When to use it
Use Wireless Diagnostics when Wi-Fi is slow or drops, to tell weak signal from interference from router problems, and to pick a better channel.
Steps
Quick signal check
Hold Option and click the Wi-Fi icon in the menu bar. You'll see RSSI (signal), Noise, Tx Rate, PHY mode, channel and more for the current network.Open Wireless Diagnostics
In the same Option-click menu, choose Open Wireless Diagnostics. Ignore the assistant for now and use the Window menu.Scan nearby networks
Window › Scan lists nearby networks with their channel, band, width and signal, and suggests the best 2.4 GHz and 5 GHz channels.Watch performance
Window › Performance graphs signal, noise and rate over time. Walk around to find dead spots.Record drops
Back in the assistant, choose Monitor my Wi-Fi connection and leave it running; it logs every disconnect for a report.Terminal alternative
wdutil replaced the old airport command.sudo wdutil info
Output explained
| Value | Good | Fair | Poor |
|---|---|---|---|
| RSSI (signal, dBm) | −30 to −60 | −60 to −70 | below −70 |
| Noise (dBm) | −90 or lower | −85 | above −80 |
| SNR (RSSI minus noise) | 25 dB+ | 15–25 dB | under 15 dB |
- Tx Rate is the current link speed in Mbps; it drops as signal weakens.
- Channel shows the band and width, for example
36 (5 GHz, 80 MHz). - PHY Mode is the standard in use: 802.11ac is Wi-Fi 5, 802.11ax Wi-Fi 6/6E, 802.11be Wi-Fi 7.
Options and variations
| Flag | Meaning | Example |
|---|---|---|
| wdutil info | Current Wi-Fi state (sudo) | sudo wdutil info |
| wdutil diagnose | Create a diagnostics archive (sudo) | sudo wdutil diagnose |
| wdutil log +wifi | Enable extra Wi-Fi logging (sudo) | sudo wdutil log +wifi |
Common errors
| Error | Cause | Fix |
|---|---|---|
| SSID shows as <redacted> in wdutil | macOS hides network names from tools without Location Services permission | Expected; use the Option-click menu to see the name. |
| airport: command not found or deprecated warning | Apple removed the airport tool's functions | Use wdutil and Wireless Diagnostics instead. |
Do it in the app
When signal looks fine but things are slow, LightAtom's connections view shows whether one app is saturating the link.
Frequently asked questions
How do I check Wi-Fi signal strength on a Mac?
Hold Option and click the Wi-Fi icon: RSSI is the signal strength. −50 dBm is excellent, −67 dBm is the usual minimum for calls, below −75 dBm expect problems.
Where is Wireless Diagnostics on a Mac?
Option-click the Wi-Fi icon and choose Open Wireless Diagnostics. The app lives in /System/Library/CoreServices/Applications.
How do I find the best Wi-Fi channel on a Mac?
Open Wireless Diagnostics, then Window › Scan. The summary recommends the best channels for 2.4 GHz and 5 GHz based on nearby networks.
What replaced the airport command?
wdutil, which ships with macOS. sudo wdutil info shows the current connection details.