# Lumens to Watts Calculator

URL: https://speedycalculator.com/calculators/everyday-life/lumens-to-watts/
Last updated: 2026-10-25

> The lumens to watts calculator converts brightness in lumens into the power a bulb uses for LED, CFL, fluorescent, halogen and incandescent bulbs, and shows the equivalent incandescent wattage.

## Inputs

- Brightness (lm)
- Bulb type (efficacy)
- Custom efficacy (lm/W)

## Results

- Power
- Incandescent equivalent

## Formula

```
Watts = lumens ÷ luminous efficacy (lm/W)
Typical efficacy: incandescent 15, halogen 20, CFL 60, fluorescent tube 85, LED 100 lm/W
```

## Explanation

Since LED lighting took over, wattage is no longer a good guide to brightness – lumens are. Luminous efficacy tells you how many lumens a bulb produces per watt: a modern LED makes about 100 lm/W, while an old incandescent made about 15. That is why a 9–10 W LED replaces a 60 W incandescent.

### How to use the Lumens to Watts Calculator

- **Brightness**
- **Bulb type (efficacy)**
- **Custom efficacy**
- Every result field is editable: type into **Power** and **Brightness** plus every other field update to match.

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Enter the brightness you want and choose the bulb type (or enter its efficacy). Type a wattage into the result to find the lumens.

### Lumens and equivalent wattage

LumensIncandescentLED45040 W4–6 W80060 W8–10 W1,10075 W11–13 W1,600100 W15–18 W2,600150 W25–28 W

### Tips

- Use the figures from your own bills and product labels – prices and appliance ratings vary widely.
- Look at yearly totals: small daily costs add up and make it easier to compare options.
- Round quantities up to whole packs, rolls or bulbs when you shop.
- Re-check the numbers when prices change; most results scale directly with the unit price.

### Common mistakes to avoid

- Confusing watts (power) with watt-hours or kilowatt-hours (energy).
- Comparing prices without bringing them to the same unit first.
- Ignoring one-off costs such as installation, delivery or replacement parts.

### Inputs explained

FieldWhat to enterBrightnessIn lmBulb type (efficacy)Choose one: LED (≈ 100 lm/W), CFL (≈ 60 lm/W), Fluorescent tube (≈ 85 lm/W), Halogen (≈ 20 lm/W) …Custom efficacyIn lm/W

## Worked example

Inputs — Brightness: 800 lm; Bulb type (efficacy): LED (≈ 100 lm/W); Custom efficacy: 120 lm/W.

Results — **Power = 8 W**; Incandescent equivalent = 60 W.

## FAQ

**How many lumens is 60 watts?**
A 60 W incandescent gives about 800 lumens, the same as a 9–10 W LED.

**How many watts is 1,000 lumens?**
About 10 W for LED, 17 W for CFL or 67 W for incandescent.

**What is luminous efficacy?**
Lumens of light per watt of electricity; higher means more efficient.

**What formula does the Lumens to Watts Calculator use?**
Watts = lumens ÷ luminous efficacy (lm/W).


## Sources

- [U.S. DOE – Lumens and the Lighting Facts label](https://www.energy.gov/energysaver/lumens-and-lighting-facts-label)