Plan injector quantities for cameras and WiFi. Choose port counts, power class, and headroom easily. Get totals instantly, then download reports for crews onsite.
| Item | Quantity | Watts Each | Notes |
|---|---|---|---|
| IP Cameras | 8 | 13 | Includes IR night mode allowance. |
| Wireless APs | 6 | 18 | Moderate density, ceiling mount. |
| VoIP Phones | 20 | 7 | Standard sets, no accessories. |
| Other Devices | 4 | 25 | Door controllers and bridges. |
| Ports per Injector | 8 | Multi-port midspan unit. | |
| Watts per Port | 30 | Suitable for most devices. | |
| Headroom | 10% spare, 15% growth | Better for change orders. | |
This calculator sizes injectors using both port capacity and total power budget, then selects the larger requirement.
Notes: Many multi-port injectors also have a fixed maximum watt budget. Use the watt-per-port option conservatively if your model has a lower shared budget.
If you are close to the per-port limit, split loads across higher-power injectors or use dedicated units for high-draw devices.
Accurate injector counts start with a clean device inventory. Record each endpoint type, typical steady draw, and any peak features such as infrared camera illumination or high density radio operation. Treat nameplate ratings as worst case and validate with vendor sheets during submittals. When existing powered switch ports are available, include only ports with confirmed spare watt capacity, not just spare openings.
Injector sizing must satisfy two limits at the same time. The first is port capacity, which is simply how many endpoints can be connected. The second is total watt budget, where a multiport unit shares a combined power supply across all ports. This calculator compares both requirements and selects the higher unit count to avoid overload trips.
Construction projects rarely freeze scope. Add spare percentage for immediate substitutions and add growth percentage for planned future endpoints. Applying headroom to both device count and watts provides conservative results, which reduces last minute procurement and avoids patchwork cabling. If headroom pushes the design across a unit boundary, consider standardizing on the next size injector for simpler spares.
Injectors convert AC input into DC output, and the conversion is not perfect. Efficiency affects heat, cabinet ventilation needs, and annual energy cost. Use measured efficiency when available, and use operating hours that match the site schedule. Even modest watt increases can compound over a year, so energy figures help justify better power hardware in long runtime facilities.
Field crews work faster with a clear port plan. Use the results summary to define injector quantity, port count per unit, and the selected watts per port class. Exported CSV supports material takeoffs, while a PDF report supports approvals and coordination meetings. Always cross check against the injector model’s published shared budget and local electrical code requirements. Label each run, reserve a spare injector, and document patch panel mappings for future maintenance.
It sizes injectors by port quantity and by total watt budget, then uses the larger result. This avoids running out of ports or exceeding shared power limits on multiport units.
Use typical draw from the datasheet and include accessories like heaters or IR illumination. If you only have nameplate watts, enter that value for a conservative plan.
More endpoints usually add both ports and power. Applying headroom to counts and load reduces the chance of overloading injectors after substitutions, add ons, or future expansions.
Choose a higher per port class or use dedicated high power injectors for those endpoints. Do not assume a port will deliver more than its rated power without vendor confirmation.
Yes. Enter only the PoE ports you can actually use, with enough watt budget remaining on the switch. The calculator subtracts those ports after applying headroom.
They estimate annual energy from adjusted output watts, efficiency, and operating hours. Multiply by your electricity rate for an annual cost signal, and use unit cost to estimate injector equipment spend.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.