What’s a good Wi-Fi signal? dBm explained

How do I check Wi-Fi signal strength on a Mac?

The quick look is the Wi-Fi menu. The exact number takes one key.

1. Click Wi-Fi in the menu bar. The bars on a network’s Wi-Fi icon show the strength of its signal: more bars, stronger signal.

2. Close the menu. Then hold down the Option key and click Wi-Fi again.
3. Under the network you’re connected to, read RSSI. That’s the signal strength, in dBm.

The same details show the network’s IP address, router address, channel, band, security and 802.11 protocol. To check another spot, close the menu, move, and Option-click Wi-Fi again.

What does dBm mean?

dBm is a unit of radio power: decibels compared with one milliwatt. A Wi-Fi signal reaches your Mac as a tiny fraction of a milliwatt, so its dBm number is negative.

• Closer to zero is stronger. −48 dBm is stronger than −70 dBm.
• Every 10 dB is ten times the power. −50 dBm is ten times as strong as −60 dBm, and a hundred times as strong as −70 dBm.

That’s why a few numbers can matter: a drop from −50 to −70 dBm means the signal is a hundredth as strong.

What is a good RSSI?

RSSI, the received signal strength indicator, is your Mac’s measurement of the router’s signal, in dBm. Apple publishes the points where its devices start looking for a stronger access point on the same network:

Above that point, your Mac stays with its access point; below it, it looks for a better one. So a Mac that sits near −75 dBm where you work is at the edge of what its router covers. A reading in the −40s or −50s is 20 dB or more above that point: at least a hundred times stronger.

What do Noise and Tx Rate mean?

The Option-click details show two more numbers beside RSSI.

The gap between RSSI and Noise shows how far the signal stands above the background. Here it’s −48 against −92 dBm: 44 dB above the noise. Tx Rate is the speed of the wireless link between your Mac and the router, not of your internet.

Is a strong signal the same as fast internet?

No. Signal strength is how clearly your Mac hears the router. Internet speed depends on everything after the router: your internet plan, other devices sharing it, and the provider’s network.

This Mac links to its router at 1200 Mbps, while macOS’s own speed test measures about 935 Mbps down from the internet. To test yours, type networkQuality in Terminal. How to test internet speed on a Mac explains the results.

How do I get a stronger signal?

Apple’s steps for a cleaner signal:

1. Bring your Mac closer to the router.
2. Keep away from power cables, microwave ovens, fluorescent lights, wireless video cameras and cordless phones.
3. Clear what’s in between: metal and concrete block Wi-Fi more than wood or glass.
4. Use the 5 GHz band where you can, because Bluetooth and Wi-Fi share 2.4 GHz.
5. Let the router choose its channel automatically, or pick the one with the least interference.

If the connection keeps dropping, Mac Wi-Fi keeps disconnecting? How to find the cause walks through Wireless Diagnostics.

Questions people also ask

Is −60 dBm a good Wi-Fi signal?

Yes. It’s well above −75 dBm, where Apple says a Mac starts looking for a stronger access point, so the Mac stays with its router.

Why is my Mac’s signal different from my iPhone’s?

Each device hears the router differently. Apple notes that antennas vary from model to model, and the two may sit in different spots.

Are the Wi-Fi bars the same as RSSI?

The bars sum up the signal at a glance. RSSI is the exact number behind them, in dBm.