Wi-Fi

Weak Wi-Fi signal on a Mac

Signal strength and noise decide how fast and how stable the Wi-Fi link is. The Mac shows both values in dBm.

Applies to: All current macOS versions.Checked: 29 October 2026

Symptoms

  • The Wi-Fi icon shows one or two bars.
  • The connection is fast in one room and slow or lost in another.
  • Video calls break up when you move the Mac.

Likely causes

  • Distance from the router. The signal becomes weaker with distance. 5 GHz and 6 GHz lose strength faster through walls than 2.4 GHz.
  • Obstacles. Apple rates metal as very high interference, and plaster, concrete and bulletproof glass as high.
  • Noise. Other devices and networks add noise. A high noise level lowers the useful signal.
  • Router position. A router in a cabinet, behind a television or on the floor covers less area.

How to check

  1. Show the signal and noise of the current network.

    system_profiler SPAirPortDataType | grep -m1 'Signal / Noise'

    Output For example Signal / Noise: -58 dBm / -94 dBm. A value nearer to 0 is stronger.

  2. Subtract the noise from the signal. The result is the signal-to-noise ratio in dB.

  3. Show more details of the Wi-Fi interface.

    wdutil info

  4. Move to the place where you use the Mac. Read the values again.

How to fix it

  1. Move the Mac nearer to the router, or remove obstacles between them.

  2. Put the router in an open, central and high position.

  3. Keep the router away from metal, microwave ovens and cordless phones.

  4. If the house is large, add an access point or a mesh node. A wired connection to the node is best.

  5. Use Ethernet for a desk that stays in one place.

With Kilobat

  1. Kilobat rates the signal. −65 dBm or stronger is good, and weaker than −75 dBm is poor.

  2. Walk with the Mac and follow the signal score, four times each second. Press q to stop.

    kilobat radar --watch

  3. Save a reading under the name of the room, to compare rooms later.

    kilobat spots save "Kitchen"

  4. In the app, Signal radar is part of Kilobat Pro. The CLI is free. See Find a better Wi-Fi spot.

Questions

When does a Mac look for a better access point?

Apple says that a Mac keeps its access point until the signal is weaker than −75 dBm. A new access point must be 12 dB stronger.

Does a stronger signal always mean faster internet?

No. The internet connection or the router can still be the slow part. See Slow internet on a Mac: find which part is slow.

Sources

Sources checked on 29 October 2026. Man pages are the ones installed with macOS; open one with man <name> in Terminal.