The Full Lumens to Watts Chart: Incandescent, Halogen and LED
For decades, wattage was the unofficial measure of brightness, and it worked surprisingly well. All incandescent light bulbs used the same technology and were equally inefficient: anyone who bought 60 watts knew exactly how much light to expect. With halogen, energy-saving lamps and finally the LED, that simple world broke apart. Today completely different technologies produce the same brightness with completely different power consumption, and only the lumen figure makes them comparable.
The following chart uses the established reference values for replacing incandescent light bulbs: 25 watts corresponds to 230 lumens, 40 watts gives 470 lumens, 60 watts reaches 806 lumens, 75 watts reaches 1,055 lumens and 100 watts reaches 1,521 lumens. The halogen and LED columns show how much power each technology typically needs to reach that brightness. For LEDs we deliberately give ranges, because efficiency varies from model to model; more on that below.
| Brightness | Incandescent (old) | Halogen | LED (typical) | Typical use |
|---|---|---|---|---|
| 230 lm | 25 W | ca. 18 W | approx. 2 to 3 W | Mood lighting and night light |
| 470 lm | 40 W | ca. 28 W | approx. 4 to 5 W | Secondary lighting, small lamps |
| 806 lm | 60 W | ca. 42 W | approx. 7 to 9 W | Standard in living spaces |
| 1055 lm | 75 W | ca. 53 W | approx. 9 to 11 W | Bright reading and task lighting |
| 1521 lm | 100 W | ca. 70 W | approx. 13 to 16 W | General lighting, ceiling lights |
Remember above all the row with 806 lumens: this is the successor to the old 60-watt bulb and is still the most common figure in living spaces. If you are refitting your home, most lamp holders take light bulbs in this class; an overview of recommended models for E27 (Edison screw, ES), E14 (small Edison screw, SES) and GU10 (twist-lock spotlight cap) is in our buying guide to LED light bulbs.
The Calculation: From Watts to Lumens and Back
For everyday use you do not need a chart in your head, just two rules of thumb. First rule, for old incandescent light bulbs: multiply the wattage roughly by 10 to 15 to estimate the brightness in lumens. The range exists because large incandescent light bulbs were more efficient than small ones: a 25-watt bulb got just over 9 lumens from every watt, a 100-watt bulb just over 15. A rigid formula such as watts times 10 therefore leads clearly astray for bright bulbs; for precise values, check the chart above.
Second rule, for LEDs: divide the desired lumen figure by 100 and you land at the approximate LED wattage. Modern LED light bulbs usually sit between 80 and 120 lumens per watt, so 100 is a convenient average. A worked example: your old bedside lamp had a 40-watt bulb, so according to the chart 470 lumens. Divided by 100, that gives around 5 watts; this is exactly the class in which you find suitable LED candle and drop-shaped light bulbs.
The calculation also works in reverse. If an LED shows only its wattage, you multiply it by around 100 and get the rough brightness: an 8-watt LED therefore delivers around 800 lumens and replaces the old 60-watt bulb. For multi-bulb lamps you simply add up the lumens of all the light bulbs. A floor lamp with three lamp holders and 470 lumens each brings a good 1,400 lumens into the room, which is already a lot as indirect general lighting for a medium-sized living room; suitable models are shown in our comparison of floor lamps.
The Most Common Mistake: Watts Say Nothing About LED Brightness
The classic on the lamp shelf: two 9-watt LEDs lie side by side, so they must be equally bright. That is not true, though. One gets 720 lumens from its 9 watts, the other over 1,000, a difference of almost 40 per cent at identical consumption. The wattage of an LED describes only how much electricity it draws. How much light comes out is decided by the quality of the chips, driver and optics. Comparing LEDs by watts is like comparing engines by tank size.
Mistake number two is blind trust in replacement claims such as "equivalent to 60 watts". Such claims are meant as a guide, but they are interpreted with varying generosity; some manufacturers round up considerably. Always check the lumen figure yourself: a genuine 60-watt replacement must actually reach the 806 lumens. If the packaging says only "replaces 60 W" but shows 650 lumens next to it, you get noticeably less light than promised.
And a third point that is often overlooked: lumens describe the total luminous flux in all directions, not the perceived brightness at one spot. A spotlight with a narrow beam angle looks brighter on the dining table than an all-round bulb with the same lumen figure, because it concentrates its light. Colour temperature also changes the impression: cool white light looks subjectively brighter and more alert than warm white at the same lumens. What lies behind Kelvin figures such as 2,700 K or 4,000 K is explained in our guide to colour temperature and the Kelvin chart.
Efficiency in Lumens per Watt: The Real Quality Measure
If you take only one figure away from this article, make it this one: lumens per watt. It says how much brightness a lamp gets from the electricity it uses, and makes all technologies directly comparable. The old incandescent light bulb managed a meagre 10 to 15 lumens per watt, because it turned most of the energy into heat. Halogen managed 15 to 20, the energy-saving lamp around 60. Modern LEDs typically sit at 80 to 120 lumens per watt, and particularly efficient models clearly exceed 150.
You can work out the figure yourself in seconds: lumens from the packaging divided by watts. An LED with 806 lumens and 6 watts reaches a good 134 lumens per watt and is therefore noticeably more economical than a model that needs 9 watts for the same brightness. The EU energy label from A to G is also based at its core on this efficiency. Over the rated lifetime of a light bulb, the difference adds up to real money; how to calculate the annual cost from watts, burning time and electricity price is worked through step by step in our guide to LED power consumption.
From Chart to Lamp: Putting Lumens into Everyday Context
The conversion is half the job, the other half is the question of how much light a room needs in the first place. As a rough guideline: for comfortable home lighting, 100 to 150 lumens per square metre are often enough, in the kitchen and bathroom it can be considerably more, and at the desk more again. A living room of 20 square metres quickly ends up at 2,000 to 3,000 lumens, spread across several light sources instead of one single glaring ceiling light. The detailed guideline values with worked examples are in our guide How many lumens per room.
What matters here is the overall picture: not every single lamp has to be bright, it is the interplay that counts. A 300-lumen reading lamp next to the armchair, two dimmed wall lights and a floor lamp with 800 lumens together make a flexible lighting concept that a single 1,500-lumen ceiling light never achieves. If you are unsure which combination suits your room, our lighting calculator takes you in a few steps from the room size to the right lumen total and to specific lamp types.
Conclusion: Read the Lumens, Forget the Watts
Wattage has had its day as a measure of brightness; for LEDs it is only good for the electricity bill. Anyone buying lamps looks at lumens first: 230 for mood lighting, 470 for small secondary lamps, 806 as the living-space standard, 1,055 for reading and working, 1,521 for strong general lighting. With the rule of thumb lumens divided by 100 you find the right LED wattage, and with a look at lumens per watt you recognise efficient models at a glance. Everything else is a matter of taste: colour temperature, dimmability, shape. That is exactly what the rest of the guides section is for.