Watts used to tell you how bright a bulb was. With LED they no longer do: a 9W LED can be as bright as an old 60W bulb, and two 9W lamps from different makers can be noticeably different. The number that actually describes brightness is the lumen.
Here is how many lumens each room needs, how to work it out for your own space in two minutes, and how to read a bulb box without being misled.
On this page
- Lumens, watts and lux in one minute
- Old watts to lumens: the conversion table
- How many lumens per room
- Working it out for your own room
- One bright light or several soft ones
- Three mistakes that make a room feel dim
- The numbers, in short
- Common questions
Lumens, watts and lux in one minute
Three words appear on lighting packaging, and they measure three different things.
- Watts (W) measure how much electricity a bulb uses. Nothing more.
- Lumens (lm) measure how much light the bulb gives out in total. This is the figure to compare when you shop.
- Lux measures how much of that light lands on a surface: one lumen spread over one square metre is one lux. It is the figure lighting designers use to say whether a worktop or a desk is lit well enough.
In practice you only need two of them. Lumens tell you what a bulb gives; lux tells you what a room needs. The rest of this guide simply joins the two.
Old watts to lumens: the conversion table
Most of us still think in the old incandescent wattages. This table translates them into lumens, using the equivalences printed on UK bulb packaging.
| Old incandescent bulb | Light output to look for | Typical LED wattage |
|---|---|---|
| 25W | about 250 lumens | 2 to 3W |
| 40W | about 470 lumens | 4 to 5W |
| 60W | about 800 lumens | 7 to 9W |
| 75W | about 1,050 lumens | 10 to 12W |
| 100W | about 1,500 lumens | 13 to 15W |
The LED column is a range on purpose. Efficiency varies between bulbs, and decorative filament bulbs give fewer lumens per watt than a plain frosted LED, because part of their job is to look beautiful when they are on. If brightness matters, read the lumen figure, not the watts.
A decorative bulb like the E27 Filament Bulb is chosen for its glow as much as its output. Use it where the bulb is on show, in an open pendant or a bare wall light, and rely on other fittings for the bulk of the light. Our guide to bulb fittings explains which cap your lamp takes.
How many lumens per room
These are the lux levels we work to, with the total lumens they translate into for a typical UK room. They are a starting point for general light, not a rule, and they assume pale walls; dark walls and ceilings absorb light and push the figures up.
| Room | Lux to aim for | Total lumens, typical room |
|---|---|---|
| Living room (15m²) | 100 to 200 lux overall, more at a reading chair | 1,500 to 3,000 lm |
| Bedroom (12m²) | 100 to 150 lux | 1,200 to 1,800 lm |
| Kitchen (12m²) | 300 to 500 lux on the worktop | 3,600 to 6,000 lm |
| Dining area (10m²) | 150 to 300 lux on the table | 1,500 to 3,000 lm |
| Bathroom (5m²) | 200 to 300 lux, more at the mirror | 1,000 to 1,500 lm |
| Hallway (6m²) | 100 lux | about 600 lm |
| Home office desk | 300 to 500 lux on the desk | a 400 to 800 lm task lamp, plus room light |
Two rooms deserve a closer look.
The kitchen needs the most light of any room in the house, because you are cutting things. That light should come from several sources aimed at the worktop, not from one ceiling fitting behind your head. Our guide to lighting a kitchen sets out the three layers, and how many pendants over an island covers the most common question.
The bedroom needs the least, and it is the room most often over-lit. A bright ceiling light is useful for finding a sock; for everything else, two bedside lamps do better. See our guide to lighting a bedroom.
Working it out for your own room
You need one sum: area in square metres × lux you want = lumens you need.
A living room of 4m by 4.5m is 18m². At 150 lux, that is 18 × 150 = 2,700 lumens in total. That total can come from any combination of fittings, and it should.
For example, in that same living room:
- a ceiling light of 1,500 lumens for general light,
- a floor lamp with an 800-lumen bulb beside the sofa,
- a table lamp with a 470-lumen bulb on a console.
That is 2,770 lumens, spread across three heights, which is exactly how a well-lit room is built.
For reference, our 18W LED Ceiling Light gives 1,800 lumens of warm 3000K light, which its maker rates for a room of 8 to 15 square metres. That makes it a complete general light for a small bedroom or bathroom on its own.
One bright light or several soft ones
The total matters, but how it is shared matters more. The same 2,700 lumens feel completely different coming from one fitting or from four.
- One bright ceiling light flattens a room. Faces lose their shape, corners stay dark, and the light you notice most is the glare above you.
- Three or four sources at different heights fill the room evenly and let you dim one corner without losing the rest.
This is why we always suggest a mix: something overhead from our ceiling lights or pendant lights, something at eye level from our wall lights, and something low from table lamps or floor lamps. Our three-layer method explains the logic room by room.
Three mistakes that make a room feel dim
Buying by watts
Two 9W LED bulbs can differ by several hundred lumens. Compare lumens, always.
Forgetting the shade
A thick fabric, rattan or paper shade can absorb a large share of the light from the bulb. That is the point of a warm, diffused lamp such as the Rice Paper Table Lamp or a rattan pendant, but it means the bulb inside should be a little brighter than you would choose for a bare fitting. Our guide to lampshade sizes covers the rest.
Choosing cool light to make up for it
A room that feels dim is rarely fixed by switching to 6000K. Cool light at a low level looks clinical; warm light at the right level looks generous. Keep living spaces at 2700 to 3000K and add lumens instead. Our guide to colour temperature, room by room explains why.
The numbers, in short
- Compare bulbs by lumens, never by watts.
- Old 60W = about 800 lumens; old 100W = about 1,500 lumens.
- Lumens needed = area in m² × lux.
- Living room 100 to 200 lux, bedroom 100 to 150, kitchen worktop 300 to 500.
- Share the total across three or four sources at different heights.
- Thick shades absorb light: choose a brighter bulb inside them.
Common questions
How many lumens do I need for a living room ?
For a typical 15 to 18m² living room, 1,500 to 3,000 lumens in total, shared between a ceiling light, a floor lamp and one or two table lamps. Multiply the floor area in square metres by 100 to 200 lux to find your own figure.
How many lumens is a 60W bulb ?
About 800 lumens. When replacing an old 60W bulb, look for an LED that gives 800 lumens or slightly more, which is usually a 7 to 9W LED.
How many lumens do I need in a kitchen ?
Kitchens need the most light in the house: 300 to 500 lux on the worktop, which is roughly 3,600 to 6,000 lumens for a 12m² kitchen. Spread it across pendants, spotlights or under-cabinet light rather than one central fitting.
Are 1,000 lumens bright enough for a bedroom ?
For general light in a small bedroom, yes, and often more than enough. A bedroom needs around 100 to 150 lux, and most of the evening light should come from bedside lamps rather than the ceiling.
Do lumens or watts matter more ?
Lumens. Watts tell you how much electricity a bulb uses, lumens tell you how much light it gives. With LED the two no longer go together, so lumens are the only reliable way to compare brightness.
Does a lampshade reduce lumens ?
Yes. Fabric, paper and woven shades absorb part of the light, and darker or thicker materials absorb more. Choose a slightly brighter bulb for a lamp with a heavy shade, or rely on it for mood rather than task light.
What is the difference between lumens and lux ?
Lumens measure the total light a bulb gives out. Lux measures how much of it reaches a surface, one lumen per square metre. Bulbs are sold in lumens; rooms are planned in lux.
Still unsure ?
Send us the size of your room and the fittings you already have at contact@thelightheritage.com and we will tell you roughly how many lumens you are short of, and where to add them. We answer every message ourselves.
Browse ceiling lights, table lamps and floor lamps, or start from the room: living room, kitchen, bedroom, bathroom.
And if your lights seem bright enough but flicker when dimmed, our guide to why LED lights flicker is the next stop.
