Survey 21 August 2026 · 5 min read
Why we design for −67 dBm (and when we don't)
−67 dBm is the most quoted number in Wi-Fi design. Here's where it comes from and why it's a target, not a rule.
Ask a wireless engineer for a coverage target and you'll probably hear −67 dBm. It comes from voice and real-time application guidance: at that signal level, with a healthy noise floor, most clients sustain the data rates needed for good call quality and smooth roaming.
Signal is only half the story
Signal strength without context is meaningless. We always pair it with signal-to-noise ratio (typically 25 dB or better), co-channel interference and secondary coverage — a second AP heard well enough for clients to roam to.
When −67 dBm is too much
In very high-density spaces like stadium bowls or lecture halls, designing for strong signal everywhere can create more co-channel interference. Smaller cells with lower power and directional antennas often perform better.
When it isn't enough
Some clinical, industrial and location-based systems need stronger signal, more secondary coverage or specific placement. The vendor's design guide for those devices always wins over a generic number.
Agree acceptance criteria before design starts — then survey against them. That's how our reports judge pass or fail.
- Primary coverage target (often −67 dBm)
- Secondary coverage for roaming
- Minimum SNR
- Maximum co-channel APs
- Capacity per area
