Wi-Fi Signal Strength Explained: What dBm Numbers Mean
Is -65 dBm good? A plain guide to Wi-Fi signal strength in dBm, what counts as strong or weak, and how to improve a weak signal at home.
Wi-Fi signal strength is measured in dBm, and the numbers look strange because they're negative. The closer to zero, the stronger the signal: -45 is stronger than -70.
What the numbers mean
| Signal | In plain words | What to expect |
|---|---|---|
| -30 to -60 dBm | Strong | Full speed, everything works |
| -60 to -67 dBm | Good | Great for streaming and calls |
| -67 to -75 dBm | Okay | Browsing is fine; calls and 4K may stutter |
| -75 to -85 dBm | Weak | Slow, with dropouts |
| Below -85 dBm | Very weak | Barely usable |
Many network engineers treat -67 dBm as the minimum for reliable video calls. That's why Wifify calls anything weaker than that "Okay" rather than "Good".
Why every 3 dB matters
The dBm scale is logarithmic. Every 3 dB is roughly half or double the power, and every 10 dB is ten times. Going from -60 to -70 dBm means the signal reaching you is about a tenth as strong.
Bars are a rough summary
Phones turn dBm into bars, but every manufacturer uses different cut-offs, so "3 bars" on one phone isn't the same as on another. For comparisons, dBm is more reliable.
How to see your signal strength
- Android: open Settings, then Network & internet (or Connections), then tap your Wi-Fi network to see a signal rating. Many phones hide the dBm value, which is why apps like Wifify show it.
- iPhone: Settings only shows bars. Apple's free AirPort Utility app includes a Wi-Fi scanner (turn it on under Settings, AirPort Utility) that shows signal values.
- Mac: hold Option and click the Wi-Fi icon in the menu bar to see RSSI in dBm.
- Windows: open Command Prompt and run
netsh wlan show interfaces. Signal is shown as a percentage.
RSSI, dBm and percentages
You'll see signal described three ways. dBm is a real power measurement and the most useful for comparisons. RSSI is a relative value that most devices report in dBm anyway. Percentages and bars are friendlier but each company converts them differently, so they're best for rough checks on the same device.
Signal isn't everything
A strong signal on a crowded channel can still be slow, and a decent signal with a fast connection can feel great. That's why it helps to look at signal together with response time and speed.
How to improve a weak signal
- Move closer to the router, or move the router: see our placement tips.
- Use the far-reaching 2.4 GHz band in rooms far from the router.
- Remove obstacles: cupboards, metal, mirrors and fish tanks.
- Add a mesh point halfway to the weak room.
Measure it as you walk
Wifify's Signal tab shows your signal every second as a word (Strong, Good, Okay, Weak), in bars and in dBm, with a one-minute graph. Walk slowly through your home and you'll see exactly where it drops.