Show Wi-Fi Signal Strength (RSSI in dBm) in the Mac Menu Bar

What you need

Multimeter for macOS 13 or later, $19.99 once.
The direct download version of Multimeter from this site (the Script source isn’t in the Mac App Store version).
Apple’s command line tools for building the helper: run xcode-select --install if xcrun isn’t found.

Set it up

Build the helper once. This writes a two-line Swift file, compiles it into ~/.local/bin/wifi-rssi and runs it:

Terminal (once)

mkdir -p ~/.local/bin && cat > /tmp/wifi-rssi.swift <<'EOF'
import CoreWLAN
if let wifi = CWWiFiClient.shared().interface() { print(wifi.rssiValue()) }
EOF
xcrun swiftc -O /tmp/wifi-rssi.swift -o ~/.local/bin/wifi-rssi && ~/.local/bin/wifi-rssi

Add a Script meter with the command wifi-rssi (the folder is already on the meter’s PATH). Refresh every 5 seconds.
Set the range to -90 to -30 and the unit to dBm. Alerts on Low values: warning at -70, critical at -80.

Multimeter settings

In Customize This Meter… (from the meter’s menu):

Settings for this meter
Setting	Value
Source	Script
Command	`wifi-rssi`
Refresh every	5 seconds
Range	-90 to -30
Unit	`dBm`
Alerts	Low values: warning -70, critical -80
Label	`WIFI`
Face	Signal Bars, Sparkline or Arc Gauge

Tested: Built and run on October 29, 2026 on macOS 27: printed -48 in 0.12 seconds. The system_profiler approach took 13 seconds, past the limit.

Script meters need the direct download version of Multimeter from this site, which is the one on sale now. How commands run, the PATH they see and the 10 second limit are in the Script meters guide.

Limits

The helper reads the strength only, which needs no Location permission. Network names do, which is why it leaves them out.

Variations

Signal-to-noise and link speed

Change the print line to print(wifi.rssiValue() - wifi.noiseMeasurement()) for signal-to-noise in dB (above 25 is good), or print(wifi.transmitRate()) for the link rate in Mbps, and build it under another name.

Troubleshooting

What the meter says, why, and what to do
Symptom	Cause	Fix
The script didn’t print a number	The command failed or printed an error message instead.	Run the exact command in Terminal. If it works there, check for tools that live outside the meter’s PATH and use their full path (`which tool`).
The script took longer than 10 seconds	A slow network call. Multimeter stops scripts after 10 seconds.	Keep the `-m` timeout on curl, and refresh less often.
Scripts need the version from multimeterapp.com	This copy of Multimeter came from the Mac App Store, which can’t run scripts.	Use the direct download version, or run the command from cron or launchd and point a File meter at its output.
xcrun: error: invalid active developer path	The command line tools aren’t installed.	Run `xcode-select --install`, then build again.
Prints `0`	Wi-Fi is off or not connected.	Connect to a network.

Questions

What is a good signal?

Around -30 to -55 dBm is excellent, -55 to -67 is fine for video calls, below -70 gets unreliable and -80 is about where connections drop.

Does this work in the Mac App Store version?

Script meters need the direct download version from multimeterapp.com, because the App Store sandbox doesn’t let apps run your commands. Web Address, File and Sent Value meters work in every version.

Show Wi-Fi signal strength in your Mac menu bar