1. What is a Watts to Lumens Calculator?

Definition: This calculator converts electrical power (watts) to luminous flux (lumens) using the efficacy of the light source.

Purpose: It helps compare lighting options and estimate brightness when switching between different bulb technologies.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Lumens (lm) — Total visible light emitted
• Watts (W) — Electrical power consumed
• Efficacy (lm/W) — Light output per watt of power

Explanation: Multiply the bulb's wattage by its efficacy (lumens per watt) to determine total light output.

3. Importance of Lumens Calculation

Details: Lumens measure actual brightness, while watts measure energy consumption. This calculation helps choose energy-efficient lighting.

4. Using the Calculator

Tips: Enter the bulb's wattage and efficacy (default 80 lm/W for typical LED). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical efficacy for different bulbs?
A: Incandescent: 10-17 lm/W, CFL: 40-70 lm/W, LED: 80-120+ lm/W

Q2: Why calculate lumens instead of using watts?
A: Lumens measure brightness directly, while watts only measure energy use.

Q3: Where can I find a bulb's efficacy?
A: Check packaging or manufacturer specifications, usually listed as "lumens per watt."

Q4: How many lumens do I need for a room?
A: Living rooms typically need 1,500-3,000 lm, kitchens 3,000-6,000 lm, bedrooms 1,000-2,000 lm.

Q5: Does higher efficacy always mean better lighting?
A: Not necessarily - also consider color temperature, CRI, and beam angle for quality.