The Light Fixture Load Calculator totals a lighting circuit from fixture wattage and quantity, adds ballast or driver losses, and converts the result to current at your system voltage and power factor.
Light Fixture Load Calculator
Total a lighting circuit from fixture wattage and quantity, add driver losses, and get real power, apparent power, current, a suggested breaker and the maximum fixtures per circuit.
Fixtures
Supply
Protection
Results
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total load
--
circuit current
Notes
About Light Fixture Load Calculator
Features
- Fixture wattage x quantity
- Ballast / driver loss allowance
- Single or three phase
- Power factor applied
- Total load in W, kW and amps
How to Use
- Enter fixture wattage and quantity.
- Set ballast loss, voltage, phase and power factor.
- Read total load and circuit current.
Examples
Example: ten 36 W fixtures with 10% driver loss at 230 V and pf 0.95 -> 396.0 W total and 1.81 A.
Benefits
- Driver losses are counted rather than ignored
- The current figure feeds straight into breaker and cable choice
Frequently Asked Questions
What does this calculator do?
Total a lighting circuit from fixture wattage and quantity, add driver losses, and get real power, apparent power, current, a suggested breaker and the maximum fixtures per circuit.
Is my data stored?
No. Everything runs in your browser; nothing is uploaded, saved or logged.