A sitting room needs 15 lumens per square foot and a dining room 20, which is 161 and 215 lux on the floor; one crystal chandelier with six 5 W lamps delivers 5 to 8 of those, so treat it as one layer and plan the rest. The maths takes three minutes with a tape measure.
The target figures by room
Residential targets are written in lumens per square foot in the United States and in lux in Europe, and one converts to the other by a single factor: 1 lumen per square foot is 10.76 lux, so 15 lumens per square foot is 161 lux and 30 lumens per square foot is 323 lux. The figures below are the points of departure used in residential practice rather than a code, because EN 12464-1 sets illuminance for workplaces, at 500 lux for an office task and 100 lux for a corridor, and it does not cover dwellings. Read the last column as the light that has to arrive on the floor or the worktop, not as the light a fixture is rated at, since the two differ by the factor applied in the next section.
| Room | Target | Equivalent | Example floor area | Delivered lumens |
|---|---|---|---|---|
| Sitting room | 15 lumens per sq ft | 161 lux | 20 sq m (215 sq ft) | 3,230 |
| Dining room | 20 lumens per sq ft | 215 lux | 14 sq m (151 sq ft) | 3,010 |
| Bedroom | 8 lumens per sq ft | 86 lux | 14 sq m (151 sq ft) | 1,210 |
| Kitchen work zone | 30 lumens per sq ft | 323 lux | 10.8 sq m (116 sq ft) | 3,490 |
| Hall and stair | 8 lumens per sq ft | 86 lux | 4.3 sq m (47 sq ft) | 370 |
| Reading corner | 40 lumens per sq ft | 431 lux | 2 sq m (21.5 sq ft) | 860 |
From delivered lumens back to lamps
The lumen method connects the two: installed lumens equal the target illuminance multiplied by the floor area, divided by a utilisation factor and a maintenance factor. A decorative pendant in a domestic room is usually taken at a utilisation factor of 0.5, because half of the output lands on the ceiling, the walls and the fixture itself, and a maintenance factor of 0.8 for a clean room, which together pass 0.4 of the installed output to the working plane. A 20 sq m (215 sq ft) sitting room at 15 lumens per square foot therefore needs 3,230 delivered lumens and 8,070 installed lumens, which is 81 W of LED at 100 lumens per watt. The factors are convention rather than measurement, and a room with dark walls passes less than the 0.4 assumed here. What the plan then needs from the fixture is a socket count and a lamp figure, and the arithmetic that turns one into the other is set out in bulb bases, socket counts and installed lumens.
| Lamp type | Typical efficacy | Lamps for 8,070 installed lumens |
|---|---|---|
| LED, warm white retrofit | 80 to 120 lumens per watt | 67 W to 101 W |
| Halogen | 15 to 20 lumens per watt | 404 W to 538 W |
| Incandescent | 12 to 14 lumens per watt | 576 W to 673 W |
The five steps below are the whole method, and they work on any room in the house.
- Measure the floor in metres or feet and convert to square feet, multiplying metres by 10.76.
- Pick the target for that room from the table above and multiply it by the square footage.
- Divide by 0.4 to turn delivered lumens into installed lumens.
- Divide by the efficacy of the lamp you intend to use, at 100 lumens per watt for LED.
- Compare the result with the lamp count and the wattage ceiling on the fixture you are considering.
What our listings state, and the line that is missing
We opened our own catalogue on 19 October 2026, all 1,381 active products, and counted specification lines by product rather than by mention, so a product counts once however often the same label repeats across its specification blocks. Five lines that decide light output appear on part of the catalogue, and the sixth appears on none of it: 656 products state a light source, 160 state a power figure, 160 state the lamp count, 246 state an irradiation area, and 0 state a lumen output. A listing can therefore tell you the socket and the wattage ceiling, and it cannot tell you the light. That is not a defect of one supplier; it is how decorative lighting is sold, because the lamp is chosen by the buyer after the fixture arrives, and the figure that matters is decided in the room.
| Specification line | Products stating it, 19 October 2026 | What it answers |
|---|---|---|
| Light source | 656 | Whether the fixture takes LED, a halogen lamp or a candle lamp |
| Power | 160 | The wattage band, which is an input figure and not an output figure |
| Number of light sources | 160 | The lamp count the fixture holds |
| Irradiation area | 246 | The merchant claim for room coverage, not measured photometry |
| Lumen output | 0 | The one line that would answer the question directly |
Why six candle lamps do not reach the target
A candle lamp in a crystal chandelier is a small source inside a small shade, and the numbers are modest: a 5 W LED candle lamp at 100 lumens per watt gives 500 lumens, so six of them install 3,000 lumens and deliver 1,200 lumens to the working plane at the 0.4 factor above. In a 20 sq m (215 sq ft) sitting room that is 5.6 lumens per square foot, or 60 lux, against a target of 15 lumens per square foot and 161 lux. In a 14 sq m (151 sq ft) dining room the same fixture delivers 8 lumens per square foot and 86 lux against a target of 20 and 215. The fixture is not faulty, and it is doing what a decorative fixture does; the difference is what the second layer is for.
| Room | Target | Delivered by six 5 W lamps | Share of target |
|---|---|---|---|
| Sitting room, 20 sq m (215 sq ft) | 15 lumens per sq ft (161 lux) | 5.6 lumens per sq ft (60 lux) | 37 percent |
| Dining room, 14 sq m (151 sq ft) | 20 lumens per sq ft (215 lux) | 8.0 lumens per sq ft (86 lux) | 40 percent |
| Bedroom, 14 sq m (151 sq ft) | 8 lumens per sq ft (86 lux) | 8.0 lumens per sq ft (86 lux) | 100 percent |
| Kitchen, 10.8 sq m (116 sq ft) | 30 lumens per sq ft (323 lux) | 10.3 lumens per sq ft (111 lux) | 34 percent |
Closing the gap with layers, not a bigger fixture
Doubling the fixture is the expensive answer and it usually fails, because a larger chandelier with the same lamp count spreads the output rather than adding to it. The cheaper sequence is to add the missing lumens in a layer that can be switched on its own: four 10 W downlights install 4,000 lumens and deliver 1,600 at the same 0.4 factor, and one floor lamp with an 800 lumen lamp delivers 320. In the sitting room above, 1,200 plus 1,600 plus 320 is 3,120 delivered lumens against a 3,230 target, which leaves a shortfall of 110 lumens, or 3.4 percent, a difference the eye reads as even rather than dim. The arithmetic applies one utilisation factor to every layer, which flatters downlights mounted close to a wall, so it is a plan and not a guarantee.
Height changes the number before anything else
Illuminance falls with the square of the distance from the source, so a fixture raised from 2.4 m (7 ft 10 in) above the floor to 4.8 m (15 ft 9 in) puts a quarter of the light on the same point, and a room that met its target at the lower height misses it by 75 percent at the higher one. That relation explains why a chandelier that looks generous in a 2.7 m (8 ft 10 in) room looks dim in a 6 m (19 ft 8 in) void, and why the answer there is more lamps, a wider spread or a layer at low level rather than a larger glass body. Inverse square is geometry rather than a rule of thumb, and it assumes a compact source, which a chandelier is only roughly.
When lumens per square foot is not the right choice
The figures above describe a room in use, and a dining room held at 215 lux every evening is a room lit like an office, which is why dimming belongs in the plan rather than in the afterthought: a 3,000 lumen installation on a dimmer at 20 percent delivers 600 lumens of nominal output and reads as a different room. The measure is also the wrong instrument for a fixture bought for its silhouette in a double-height void, where the light comes from the layers below and the chandelier is read against a dark ceiling; for a room where the work is reading at 40 lumens per square foot on the page rather than on the floor; and for a space with dark walls and a dark floor, where the same installed lumens deliver less than the table predicts. A bathroom asks the same arithmetic of a much smaller floor area, and there the position of the fixture is settled by a code zone rather than by a lumen count, as set out in hanging a chandelier over a bathtub.
Where the room is a dining room, the tabletop figure matters more than the room average, and how much light a dining table needs works the calculation from the surface upward. Where the extra layer is being built into the ceiling, cove lighting dimensions covers the output per metre that an indirect layer adds, and downlight beam angle covers the spacing that keeps a cone off the fixture. The order in which those layers are decided is in lighting schedule and rough-in. Fixtures whose wattage ceiling and lamp count are stated on the listing are in our chandelier collection.
Numbers and sources
The catalogue figures come from our own Shopify export of 19 October 2026, 1,381 active products, counted by product against the specification labels inside the product descriptions rather than against the description text, so a product that repeats a label twice is counted once. A declared wattage or lamp count describes what a listing states and not what a fixture emits, because the output follows the lamp the buyer installs. The conversion, the lumen method and every room example were recalculated from the formulas below rather than copied from a table, and the target figures are points of departure used in residential practice, which is a different kind of claim from a standard. Nothing here promises a delivered light level in a particular room: illuminance is confirmed with a meter after installation, with the lamps that will actually be used in the fixture.
| Figure | Value | Source | Nature |
|---|---|---|---|
| Conversion | 1 lumen per sq ft = 10.76 lux | Unit definition | Arithmetic |
| Residential targets | 8 to 40 lumens per sq ft by room | Residential lighting practice | Convention, not a standard |
| Workplace reference | 500 lux office task, 100 lux corridor | EN 12464-1 | Standard, workplaces only |
| Utilisation and maintenance factor | 0.5 and 0.8, product 0.4 | Lumen method convention | Convention, not measured |
| Lamp efficacy | 80 to 120 lm/W LED, 15 to 20 halogen, 12 to 14 incandescent | Lamp industry typical values | Typical range, not a specification |
| Catalogue size | 1,381 active products | Shopify export, 19 October 2026 | First party, recomputed |
| Light source line | 656 products | Same export, specification labels | First party, recomputed |
| Power line | 160 products | Same export, specification labels | First party, recomputed |
| Number of light sources | 160 products | Same export, specification labels | First party, recomputed |
| Irradiation area | 246 products | Same export, specification labels | Merchant claim, not photometry |
| Lumen output | 0 products | Same export, all labels and description text | First party, recomputed |
| Six 5 W lamps | 3,000 installed, 1,200 delivered | Lumen method at 0.4 | Calculated, not measured |
| Inverse square | Quarter of the illuminance at double the height | Point source geometry | Calculated, not measured |