Determine your required circuits, total current draw, and generator size based on your connected load.
Note: This tool sizes your power supply needs. To estimate the utility billing cost of running this rig, use the Studio Electricity Cost Calculator.
A lighting package can exceed available electrical capacity long before every fixture is switched on. Tungsten fixtures, LEDs, HMIs, cameras, monitors, grip equipment, effects, and other production loads all contribute to the supply requirement.
The Lighting Power Calculator turns that equipment list into a practical power estimate. It calculates Total Current Draw, Circuits Required, and Generator Size, while also showing connected wattage, demand load, usable load per circuit, and remaining circuit headroom.
Use the calculator when planning a studio lighting rig, checking available supply, or estimating generator capacity before production. It sizes electrical demand only. It does not calculate electricity cost.
This is a planning estimate, not an electrical design. Actual installations, temporary distribution, generators, phase loading, grounding, cable sizing, protection devices, connectors, and code compliance should be reviewed and approved by a qualified licensed electrician or other appropriately qualified professional.
The calculator begins by converting each fixture group into electrical watts.
For tungsten fixtures:
Tungsten load = Tungsten fixture count × Average tungsten wattage
For LEDs:
LED load = LED fixture count × Average LED wattage
The LED value should be actual electrical draw at full output, not an advertised tungsten-equivalent output. A fixture marketed as producing light comparable to a 1,000 W tungsten lamp may draw only a fraction of that power.
HMIs require an additional ballast-efficiency adjustment:
HMI load = (HMI fixture count × Average HMI wattage) ÷ (Ballast efficiency / 100)
The calculator also adds camera, video, grip, and effects loads before applying the Simultaneous Use Factor.
Connected load = Tungsten + LED + HMI + Other loads
Demand load = Connected load × (Simultaneous use factor / 100)
Connected load assumes everything is drawing at once. Demand load estimates the portion expected to operate simultaneously.
Build the load from the fixture package first, then enter the electrical supply and generator assumptions.
For tungsten, enter Tungsten Fixture Count and Average Tungsten Wattage. Include Fresnels, open-face fixtures, practicals, and other tungsten sources that will be supplied through the modeled system.
For LED fixtures, enter LED Fixture Count and Average LED Wattage. Use the actual electrical draw at full output. Do not enter the fixture’s equivalent light-output rating.
For HMIs and other discharge sources, enter HMI Fixture Count and Average HMI Wattage using the lamp rating. Then set Ballast Efficiency, which defaults to 90 percent. Lower ballast efficiency produces higher electrical draw because more input power is required to supply the lamp.
Enter Camera and Video Load for cameras, monitors, video village equipment, racks, wireless systems, and similar production electronics supplied from the same power plan.
Use Grip and Effects Load for fans, smoke machines, motors, practical effects, and other electrical equipment outside the three fixture categories.
Including these loads helps avoid sizing the electrical supply around lighting alone when significant production equipment shares the same source.
Set Supply Voltage to the voltage being modeled. The interface defaults to 120 V for standard US circuits and also notes 208 V for three-phase line-to-line supply.
Choose Supply Type as Single phase or Three phase.
For single phase:
Total current draw = Demand watts ÷ Supply voltage
For three phase:
Amps per leg = Demand watts ÷ (Supply voltage × 1.732)
Enter Breaker Rating for one modeled circuit. The default is 20 A.
Use Continuous Load Derate to define the portion of that breaker rating available to the calculation. The default is 80 percent.
Usable circuit amps = Breaker rating × (Derate / 100)
Usable load per circuit = Usable circuit amps × Supply voltage
The calculator always rounds circuit count upward.
Circuits required = CEILING(Demand load ÷ Usable load per circuit)
If the result is 11.9 circuits, the requirement is 12 circuits. A fractional circuit cannot supply the remaining load.
Set Simultaneous Use Factor to the percentage of connected equipment expected to operate at the same time. The default is 85 percent.
Use Generator Sizing Margin for additional headroom above demand. The default is 25 percent.
Enter Power Factor, default 0.8, to convert the generator requirement from kW to kVA.
Generator kW = Demand watts × (1 + Generator margin / 100) ÷ 1,000
Generator kVA = Generator kW ÷ Power factor
The outputs separate connected equipment from expected demand and show whether the modeled circuit capacity leaves useful headroom.
Connected Load represents the wattage if every entered load operates simultaneously.
Demand Load applies the Simultaneous Use Factor and becomes the basis for current draw, circuit count, and generator sizing.
In single-phase mode, Total Current Draw expresses demand in amps. In three-phase mode, the calculator reports Amps per Leg using the supplied three-phase formula.
These are aggregate planning values. A real distribution plan must also consider how individual loads are assigned and balanced across circuits and phases.
Circuits Required shows the number of modeled breakers needed after the Continuous Load Derate.
Installed usable capacity is:
Installed capacity = Circuits required × Usable load per circuit
The unused portion is:
Spare circuit capacity = Installed capacity – Demand load
The calculator also expresses this as a percentage of installed capacity.
A spare-capacity result over 25 percent is labeled Headroom Available, 10 to 25 percent is Adequate, and under 10 percent is At Capacity.
These badges are planning signals. An At Capacity result means the modeled circuit group has very little room for additional load and should be reviewed before the rig grows.
Generator Size is reported in kVA after applying the selected sizing margin and power factor. It is a capacity estimate, not a recommendation for a specific generator or distribution system.
The Load Breakdown table separates Source, Fixtures, Watts, Amps, and Share of Connected Load.
The calculator also reports Tungsten Share of Connected Load, making it easier to see when traditional fixtures dominate the electrical requirement.
Consider a rig with eight 2,000 W tungsten fixtures, 24 LEDs drawing 150 W each, and four 1,200 W HMIs operating through 90 percent efficient ballasts.
Tungsten contributes:
8 × 2,000 = 16,000 W
LED contributes:
24 × 150 = 3,600 W
HMI demand including ballast losses is:
(4 × 1,200) ÷ 0.90 = approximately 5,333 W
Add 1,200 W of camera and video load plus 800 W of grip and effects load.
Connected load becomes approximately 26,933 W.
At an 85 percent Simultaneous Use Factor:
26,933 × 85% = approximately 22,893 W demand
On a 120 V single-phase supply:
22,893 ÷ 120 = approximately 190.8 A
Using 20 A breakers at an 80 percent continuous-load derate leaves 16 usable amps per modeled circuit.
16 × 120 = 1,920 W usable per circuit
The demand therefore requires:
CEILING(22,893 ÷ 1,920) = 12 circuits
Twelve circuits provide 23,040 W of modeled usable capacity, leaving only about 147 W, or 0.6 percent, as spare capacity. That places the example in the At Capacity range.
With a 25 percent generator margin:
22,893 × 1.25 ÷ 1,000 = approximately 28.6 kW
At a 0.8 power factor, the modeled generator requirement is approximately 35.8 kVA.
Tungsten represents about 59.4 percent of the connected load, making it the dominant power source in this example.
Use the calculator to compare rig options before equipment reaches the stage.
If the system is At Capacity, first identify which load category is driving demand. Replacing high-wattage tungsten units with lower-draw fixtures where creatively appropriate can materially reduce connected load. Adjusting simultaneous-use assumptions may also change demand, but only when the lower figure accurately reflects how the rig will operate.
Do not reduce the Continuous Load Derate or electrical safety margin simply to make an existing supply appear sufficient. Circuit loading, conductor capacity, breaker selection, distribution, phase balancing, grounding, connector ratings, and local electrical requirements need professional review.
The calculator also helps identify generator headroom during planning, but generator selection should account for the actual equipment package, starting behavior, distribution arrangement, environmental conditions, and electrical requirements.
Electrical estimates are more useful when lighting inventories, equipment assignments, production plans, and facility information remain current.
Studio Hero connects scheduling, projects, crew coordination, budgeting, invoicing, equipment tracking, inventory, client workflows, and media assets in one connected studio management system.
Studio Hero’s studio operations management capabilities help teams keep facility activity, production resources, equipment, and operational information connected as stage requirements change.
Enter actual electrical draw at full output. Do not use the tungsten-equivalent or marketing output rating.
The HMI input uses lamp wattage, while the ballast also consumes power. Ballast Efficiency accounts for that additional electrical demand.
Electrical demand cannot be supplied by part of a circuit. The calculator therefore uses a ceiling function so any fractional circuit requirement becomes the next whole circuit.
It estimates the share of connected equipment expected to draw power at the same time. Use a realistic operating assumption rather than automatically entering 100 percent or reducing the factor simply to lower the result.
No. It estimates aggregate demand and amps per leg from the supplied formula. Actual phase balancing, breaker assignments, cabling, distribution, grounding, and protection require qualified electrical design.
Yes. The calculation applies the selected Generator Sizing Margin before converting kW to kVA using the entered Power Factor.
No. It calculates watts, amps, circuits, and generator capacity. Electricity consumption and operating cost belong to a separate cost calculation.
No. The calculator is for preliminary planning. A licensed electrician or appropriately qualified electrical professional should verify the real installation, temporary distribution, and generator system before use.
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