Lux versus lumens, in one line
A lumen is what leaves the lamp. A lux is what arrives on the table. The same 1,000-lumen fitting gives roughly 100 lux at one metre and 25 lux at two metres, because illuminance falls with the square of distance. This is why a shop’s wattage recommendation is useless without a ceiling height, and why two flats with identical fittings can measure completely differently.
Targets we design to
| Space | Target lux | Measured at |
|---|---|---|
| Living room, general | 150–200 | Floor level |
| Dining table | 200–300 | Table top |
| Kitchen worktop | 300–500 | Counter, 850 mm |
| Study or home office desk | 300–500 | Desk, 750 mm |
| Bathroom mirror | 300–500 | Face height, from the front |
| Bedroom, ambient | 100–150 | Floor level |
| Open-plan office | 300–400 | Desk, per IS 3646 |
| Circulation, passage | 75–100 | Floor level |
Two related numbers belong on a lighting plan alongside the target. Maintained lux is the level after depreciation and dust, which is what you actually live with. Uniformity is the ratio of minimum to average across a work plane; below about 0.6 a counter reads as patchy however high the average measures.
Why the room matters as much as the fitting
Reflectance changes measured lux by a third or more. An off-white ceiling at 80% reflectance and pale walls bounce light back into the room; a walnut veneer wall at 12% reflectance swallows it. We routinely add 20–30% to the fitting count in a dark-material scheme, and we reduce it in a white minimal flat. Depreciation matters too: allow 10–15% loss over the life of an LED and a further margin for dust on diffusers.
Lux is also a measurement you can check for yourself. A phone light meter is approximate but honest about gross errors, and a ₹3,000 handheld meter is accurate enough to argue with. Test at night with curtains drawn, at the height the task actually happens.
Use the lumens calculator to convert a target lux into a fitting count, then check the beam angles against downlight spacing. For a whole scheme, our residential team issues a lighting plan with lux targets on it.
Frequently asked questions
How many lux is good for a living room?+
150–200 lux for general use, with a lamp or accent layer that lets you drop to 50–80 lux in the evening. A single number for a whole room is a poor brief: design the general layer to 150 and add task light where people actually read.
Is 500 lux too bright for a home?+
Not on a worktop or a desk, where 300–500 lux is correct. Across a whole living room it is clinical. The mistake is applying an office target to a home, then wondering why the flat feels like a bank branch.
Can I measure lux with my phone?+
Roughly. Phone sensors under-read at low levels and vary between handsets, but they reliably tell you whether a desk is at 100 lux or 400. For any specification argument, use a calibrated meter.
What lux level do Indian offices need?+
IS 3646 puts general office work at 300–400 lux on the desk, with 500 lux for detailed drawing or inspection work and 150–200 for circulation. Most fit-outs over-light the field and under-light meeting rooms.