Access Control Door Planner: engineer's guide
Access control planning ties reader count, controller port capacity, cable pulls, and power budget into a coordinated design.
Open the Access Control Door Planner →
What this calculator does
The calculator sums doors by type (single-side, double-side, mag-lock, strike), assigns controller ports, and reports the PoE/24 VDC budget.
Formulas used
- Controllers required:
Nctrl = ⌈Ndoors / doors-per-controller⌉ - Power budget:
Ptotal = Σ (N × Wdevice)
Variables
- doors-per-controller = 2, 4, 8, 16 depending on model
- Wdevice = reader 3 W, mag-lock 8 W, strike 12 W
Worked example
Scenario: 40 access-controlled doors: 32 single-side card readers + 8 double-side (biometric out, card in).
- Reader count: 32 + 16 = 48 readers
- 4-door controllers required = 40 / 4 = 10 controllers
- Reader power: 48 × 3 = 144 W. Lock power: 40 × 10 = 400 W
- Central UPS at 800 VA for 4-hour standby
Common mistakes to avoid
- Under-budgeting standby power for mag-locks (fail-safe drops on power loss)
- Missing REX/exit device provision
- No integration to fire alarm for fail-safe on evacuation
- Long cable runs on 24 VDC without voltage drop check
Frequently asked questions
Fail-safe or fail-secure?
Mag-locks on egress doors must be fail-safe (drop on power loss) — interlocked to fire alarm.
PoE for readers?
PoE simplifies cable pulls; use IEEE 802.3af or at, depending on reader.
Standards and references
BS EN 60839, UL 294, NFPA 101 (egress)
Related tools on this site
Open the calculator that pairs with this guide: Access Control Door Planner.
Verification note
This guide is planning support only. Final design must be verified against the applicable project specification, authority requirements, manufacturer data, and the standards cited above. Consult a licensed engineer for construction-issue calculations.