Lumen, lux and watt: how much light do you need
Watts once told us how bright a bulb would be. With LEDs, lumen and lux have taken over. What the three words mean, and how to work out the right amount of light for each room.
Lumen Calculator
Lumen calculator: how much light does a room need
Choose the room, enter its size and get the lumens for general light, the number of bulbs and the LED wattage.
Old bulb, new LED
| Former incandescent | LED with at least |
|---|---|
| 25 W | 249 lm |
| 40 W | 470 lm |
| 60 W | 806 lm |
| 75 W | 1,055 lm |
| 100 W | 1,521 lm |
An estimate for general light, based on typical guidance values and a loss factor for shades, walls and ageing. Spread the light over several lamps at different heights, and add task light where you read, cook or work.
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