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
| Lumens | Incandescent | LED |
|---|---|---|
| 450 | 40 W | 4–6 W |
| 800 | 60 W | 8–10 W |
| 1,100 | 75 W | 11–13 W |
| 1,600 | 100 W | 15–18 W |
| 2,600 | 150 W | 25–28 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
| Field | What to enter |
|---|---|
| Brightness | In lm |
| Bulb type (efficacy) | Choose one: LED (≈ 100 lm/W), CFL (≈ 60 lm/W), Fluorescent tube (≈ 85 lm/W), Halogen (≈ 20 lm/W) … |
| Custom efficacy | In lm/W |
Formula
Watts = lumens ÷ luminous efficacy (lm/W)Typical efficacy: incandescent 15, halogen 20, CFL 60, fluorescent tube 85, LED 100 lm/WWorked 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.
Frequently asked questions
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).