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Lumens to Watts Calculator

Convert between light brightness (lumens) and power consumption (watts)

Convert Lumens ↔ Watts

Most energy-efficient option

Light Brightness

Typical range: 200-5000 lumens for household bulbs

Calculation Results

Required Power

12.00 W
1200
Lumens
12.00
Watts
100.0
lm/W

Efficiency Rating

Excellent
Very energy efficient
100.0 lm/W
LED

Bulb Type Comparison

Power consumption for 1200 lumens across different bulb types:

Low-Pressure Sodium
8.3W1.4x less power
High-Pressure Sodium
10.4W1.2x less power
LED
12.0W1.0x less power
Metal Halide
14.1W1.2x more power
Sulfur Plasma
16.0W1.3x more power
Fluorescent Tube
17.1W1.4x more power
Compact Fluorescent (CFL)
20.0W1.7x more power
Mercury Vapor
24.0W2.0x more power
Halogen
52.2W4.3x more power
Incandescent
80.0W6.7x more power

Energy Savings: LED bulbs use up to 7x less power than incandescent bulbs for the same brightness!

Conversion Formulas

Watts from Lumens

P(W) = Φ_V(lm) ÷ η(lm/W)
Power = Luminous Flux ÷ Luminous Efficacy
Example: 1200lm ÷ 100lm/W = 12.00W

Lumens from Watts

Φ_V(lm) = P(W) × η(lm/W)
Luminous Flux = Power × Luminous Efficacy
Example: 12W × 100lm/W = 1200lm

Luminous Efficacy

η(lm/W) = Φ_V(lm) ÷ P(W)
Luminous Efficacy = Luminous Flux ÷ Power
Example: 1200lm ÷ 12W = 100.0lm/W
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Bulb Efficiency Chart

Low-Pressure Sodium
100-190 lm/W
145 lm/W
High-Pressure Sodium
85-150 lm/W
115 lm/W
LED
80-120 lm/W
100 lm/W
Metal Halide
75-100 lm/W
85 lm/W
Sulfur Plasma
50-100 lm/W
75 lm/W
Fluorescent Tube
40-105 lm/W
70 lm/W
Compact Fluorescent (CFL)
45-75 lm/W
60 lm/W
Mercury Vapor
35-65 lm/W
50 lm/W
Halogen
16-30 lm/W
23 lm/W
Incandescent
12-18 lm/W
15 lm/W

Quick Reference

💡

Lumens (lm)

Total amount of visible light emitted

⚡

Watts (W)

Electrical power consumed

📊

Efficacy (lm/W)

Light output per unit of power

🔆

Nits (cd/m²)

Brightness per unit area (displays)

Energy Saving Tips

💰

Choose LED bulbs for maximum energy efficiency

💰

Look for ENERGY STAR certified bulbs

💰

Consider dimmable options for variable brightness

💰

Replace highest-usage bulbs first for maximum savings

💰

LEDs last 15-25x longer than incandescent bulbs

Understanding Lumens, Watts, and Efficacy

Key Concepts

  • •Lumens: Measure of total visible light output from a source
  • •Watts: Measure of electrical power consumption
  • •Luminous Efficacy: Efficiency of converting power to visible light
  • •Nits: Brightness per unit area, common for displays

Remember: Higher lumens = brighter light. Higher efficacy (lm/W) = more efficient bulb.

Why This Matters

  • •Energy Bills: More efficient bulbs cost less to operate
  • •Environment: Lower power consumption reduces carbon footprint
  • •Replacement: When switching bulb types, match lumens, not watts
  • •Heat: Efficient bulbs produce less waste heat

LED Advantage: An LED bulb uses about 75% less energy and lasts 25x longer than incandescent bulbs.

Common Bulb Equivalents

Soft White

800 lumens

60W incandescent = 8-12W LED

Bright White

1600 lumens

100W incandescent = 16-20W LED

Daylight

2600 lumens

150W incandescent = 25-28W LED

High Output

5000+ lumens

300W+ incandescent = 50W+ LED

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