How Many WiFi Access Points Do You Need? AP Placement & PoE Power Planning
Buying the right access point is half the job — placing the right number of them and powering them correctly is the other half. Here is how to estimate AP count by square footage and density, where to mount them, and which PoE standard (802.3af/at/bt) each WiFi generation needs.
TL;DR — count, place, power
- How many? HPE Aruba's starting point for an open office is APs 30-50 ft apart, which is about 780-2,170 sq ft per AP, and 30-40 connected devices per AP. Use whichever gives more APs; the WiFi planner works out both.
- Where? Ceiling-mounted, centered over the coverage area, with overlap between APs for seamless roaming.
- Signal target? At least -67 dBm where voice is used, with two APs heard at that level (Cisco).
- Power? 802.3af (15.4W) powers most 2x2 WiFi 6 APs; 802.3at / PoE+ (30W) for 4x4 WiFi 6 and many WiFi 6E APs; 802.3bt (60-90W) for high-end WiFi 6E/7 with multiple radios.
This is the planning the WiFi 6 AP buying guide and WiFi 6 vs 6E vs 7 comparison lead into.
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Estimating AP count
Two factors, take the larger:
- Coverage — HPE Aruba's starting point for a typical open office is APs 30-50 ft apart. In a staggered layout that is about 780-2,170 sq ft per AP. Dense materials such as cinder block need closer spacing, and warehouses or manufacturing floors may need a physical survey.
- Capacity (density) — HPE Aruba plans for 30-40 clients per AP, assuming 2.5 WiFi devices per person with half connected at once. That is roughly 24-32 people per AP, so 200 people need 7-9 APs for capacity alone. A 200-seat office is a density problem, not a coverage problem.
High-density spaces (lecture halls, conference centers, stadiums) are planned by client count per AP, often with lower transmit power and more APs packed closer.
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Placement rules that actually matter
- Ceiling mount, centered over the space — APs radiate down and out.
- Overlap about 20% between adjacent cells at -67 dBm for voice (Cisco), so clients roam without dropping.
- Avoid obstructions — metal, concrete, elevator shafts, and mirrors kill signal. HPE Aruba says not to install APs above drop ceilings, and to keep them clear of columns, beams and furniture.
- Don't over-power — cranking transmit power to "cover more" causes co-channel interference and sticky-client roaming problems. More, lower-power APs beat fewer, blasting APs.
- Outdoor/warehouse — use APs rated for the environment and the right antennas (omni vs directional).
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Signal target: what -67 dBm means
Cisco's site survey guidance gives -67 dBm as the minimum recommended signal for voice, with a signal-to-noise ratio of 25 dB, and at least two APs heard at -67 dBm or better at all times. For WiFi 6 and 6E, HPE Aruba sizes cells for -55 to -65 dBm at the edge, depending on capacity needs. Raising AP power does not fix a weak link on its own: Cisco notes it only increases coverage on the downlink, and advises keeping AP power no higher than client devices support.
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PoE: powering your APs
Access points are almost always PoE-powered over the same Ethernet cable that carries data. Match the standard to the AP:
| PoE standard | At the switch port | At the device | Powers |
|---|---|---|---|
| 802.3af (PoE) | 15.4W | 12.95W | Most 2x2 WiFi 5 / WiFi 6 APs |
| 802.3at (PoE+) | 30W | 25.5W | 4x4 WiFi 6, many WiFi 6E APs |
| 802.3bt (PoE++ Type 3/4) | 60W / 90W | 51W / 71.3W | High-end WiFi 6E / WiFi 7, multi-radio APs |
The last column is a general guide: check each AP's datasheet for its PoE class and maximum draw.
For three or more APs, power them from a PoE switch rather than individual injectors, and budget the switch's total PoE wattage — a switch rated "370W PoE budget" can't run 24 PoE+ APs at 30W each. See the PoE switch buying guide. (PoE wattage per the IEEE 802.3af/at/bt standards.)
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Don't forget the controller (or cloud)
More than a few APs usually want central management — a wireless LAN controller or a cloud-managed platform (Meraki vs Aruba Instant On vs UniFi) — for roaming, channel planning, and one-pane config.
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FAQ
How many APs for a 10,000 sq ft office? About 5-13 for coverage (APs 30-50 ft apart), and more if high device density calls for it. The WiFi planner checks both.
What signal strength should I design for? At least -67 dBm where voice is used, with two APs heard at that level (Cisco). HPE Aruba sizes WiFi 6 and 6E cells for -55 to -65 dBm at the edge.
Mesh or access points? Mesh suits homes and small offices without cable; see mesh WiFi vs access points.
Can one PoE switch power all my APs? Only within its PoE budget. Add the per-AP wattage and confirm the switch's total PoE capacity (and use PoE+ ports for hungrier APs).
Ceiling or wall mount? Ceiling, centered, for most indoor APs. Wall-mount only with APs/antennas designed for it.
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Pro Disk Network is an independent reseller of genuine enterprise APs and PoE switches (HPE/Aruba, Cisco/Meraki, Ubiquiti, and others; not affiliated with those vendors). Related: enterprise WiFi 6 AP buying guide · PoE switch guide.
PoE power levels per IEEE 802.3af/at/bt. Coverage and capacity figures are starting points from HPE Aruba's Validated Solution Guide on RF design; a site survey gives exact AP counts.