Lighting

LED Wattage Calculator

Convert a lumen target into LED wattage using the lamp’s real efficacy.

Free interactive tool

Enter your details

lm
lm/W
Method & guidance

How the LED Wattage Calculator works

Required lumens are divided by lumens per watt and rounded up for purchasing.

How to use this tool

  1. Collect accurate values for required lumens, led efficacy, number of fixtures.
  2. Enter measurements in the displayed units and select the choices that match this project.
  3. Select Calculate / Generate, then compare the outputs with the stated LED Wattage Calculator method.
  4. Apply the result only after checking product specifications and real site conditions.

Example calculation or use case

For a worked LED Wattage Calculator example, use Required lumens = 3000 lm, LED efficacy = 90 lm/W, Number of fixtures = 4. The tool then applies this method: Required lumens are divided by lumens per watt and rounded up for purchasing.

Frequently Asked Questions

What information does the LED Wattage Calculator use?

It uses the measurements and choices shown in the form. Required lumens are divided by lumens per watt and rounded up for purchasing.

How accurate is the LED Wattage Calculator result?

The calculation is mathematically consistent with the stated assumptions. Compare delivered lumens, color temperature, CRI, and dimmer compatibility—not wattage alone. Real products, site conditions, and supplier specifications can still change the final decision.

Should I include an allowance?

Use the result as a planning baseline and keep a sensible reserve for site variation, delivery, or fitting.

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