Lighting Power Calculator

Total Wattage is the raw electrical power the lights draw, found by multiplying the number of fixtures by the wattage of each one. Total Amps converts that power figure into current by dividing by your mains voltage, which is the number breakers and circuit panels actually care about when deciding how much load a circuit can safely carry.

Total Wattage only depends on how many lights you're running and how many watts each one draws -- voltage plays no role in that multiplication. Voltage matters for Total Amps and Circuits Needed instead, since the same wattage pulls fewer amps at a higher voltage, which is why 240V setups often need fewer reserved circuits than 120V ones for the same lighting package.

It divides Total Amps by 16, which is the usable capacity of a standard 20-amp circuit derated to 80% for continuous loads, then rounds up to the next whole circuit. Rounding up matters because a circuit running right at its rated maximum for hours on a shoot day is a real breaker-tripping and fire-safety risk, not just an inconvenience.

It converts your total lighting wattage into BTU per hour using the standard watts-to-BTU conversion, giving you a rough sense of how much additional heat the lights will add to a room or stage. That number is useful for anticipating HVAC strain on a hot shoot day, though it doesn't account for a space's actual cooling capacity or insulation.

No -- Hours per Day only affects Energy per Day, the cumulative kWh figure used for budgeting or generator fuel planning. The instantaneous electrical load represented by Total Wattage, Total Amps, and Circuits Needed is the same whether the lights run for thirty minutes or the entire day; only the running total of energy consumed changes.