Lighting Load Calculator

Estimate lighting load from fixture wattage, quantity, floor area, watts per square foot, voltage, power factor, demand factor, and continuous load factor. This calculator shows lighting watts, VA, amps, kW, kVA, circuit load, panel capacity percentage, and energy cost.

Calculate Lighting Load

Lighting load = total lighting watts ÷ power factor. Adjusted amps may include demand factor and continuous load factor.
Your result will appear here.

How the lighting load calculator works

Total watts:
The calculator totals lighting watts from fixtures, floor area, manual entry, or detailed fixture rows.

VA and amps:
Lighting VA is estimated from watts and power factor, then converted to amps using voltage and phase type.

Adjusted load:
Demand factor and continuous load factor can be applied to estimate adjusted amps and capacity percentage.

Why use a lighting load calculator?

A lighting load calculator helps estimate how much electrical load lighting adds to a room, building, circuit, panel, subpanel, generator, or service.

It can help with LED lighting upgrades, shop lighting, commercial lighting, residential lighting, exterior lighting, panel planning, circuit planning, and energy cost estimates.

What your result means

Your result shows lighting watts, lighting VA, lighting amps, adjusted amps, kW, kVA, watts per square foot, VA per square foot, circuit capacity percentage, remaining amps, monthly kWh, monthly cost, yearly cost, and detailed fixture row totals.

Lighting load calculator formulas

Frequently asked questions

How do I calculate lighting load?

Multiply fixture watts by the number of fixtures, or multiply floor area by watts per square foot. Then convert watts to VA and amps if needed.

What is lighting VA?

Lighting VA is the apparent load used for electrical planning. It can be higher than watts when the power factor is below 1.00.

Do lighting loads count as continuous loads?

Lighting may be treated as continuous when it is expected to run for long periods. In that case, a 125% factor is often used for planning.

Can this calculator size the final lighting circuit?

No. This calculator gives planning estimates. Final circuit sizing should follow fixture nameplates, electrical code, conductor sizing, breaker ratings, voltage drop, and local inspection requirements.