Our answer: 2700K warm white for the rooms you relax in, 3000K over a kitchen worktop, and around 4000K at a bathroom mirror, in a utility room or at a desk used by day. Those are the starting points we give anyone who is unsure, and the reasoning for each is below. They are our recommendations, not rules. A different figure that you like in your own room is not a wrong one.
Two numbers on the box do two different jobs. The Kelvin figure, written K, describes the colour of the light: low numbers look golden, higher ones whiter and then bluer. Lumens describe how much light the bulb gives. A warm bulb can be bright and a cool one can be dim, so choose the two separately. The words printed around those numbers are much less reliable than the numbers themselves.
What do warm white, neutral white and cool white mean?
The names on the packet are not standardised. In our own range the words 'cool white' appear on a 4000K crystal golf ball bulb and on a 6000K golf ball bulb, two quite different colours. Compare the number, not the adjective.
| Kelvin | How it usually looks | Where we would start |
|---|---|---|
| 1800K to 2200K | Very golden, amber | Decorative filament bulbs on show, where a candle-like glow is the point |
| 2700K | Warm white | Living rooms, dining rooms, bedrooms, hallways and table lamps. Our default |
| 3000K | Warm white, a little crisper | Kitchen worktops, reading corners, bathroom ceilings, outside |
| 4000K | Neutral white, sold as natural white or cool white | Bathroom mirrors, utility rooms, garages, a desk used by day |
| 5000K to 6500K | Cooler, often labelled daylight | Workshops and specialist tasks. We would not choose it for a room you relax in |
'Daylight' on a box names a colour. It does not promise the bulb behaves like daylight in every other way: how well it shows colours, how much light it gives and how the fitting spreads it all matter too. The step we would think hardest about is 3000K to 4000K. Below it, suppliers call the light warm white; at 4000K the names change to natural or cool white, and to our eye the character of a room changes with them.
Living room: start at 2700K
2700K is where we would start, on the ceiling and on every lamp. It is warm without being orange and it is the figure we would choose for a relaxed evening room. If your scheme is very pale and modern, or you simply prefer a cleaner look, try 3000K. Either way, fit one bulb and look at it with your own walls, shades and other lights on before you replace the lot.
If you already have 4000K in a sitting room and you like it, you have not bought the wrong bulb. Our recommendation is for people who are unsure, not a verdict on people who are not.
For a candle fitting with an E14 cap, the Candle E14 LED bulb 4W 2700K (£5.41, checked 19 October 2026) states its colour in the title and gives 470 lumens; it is not dimmable. On a dimmer, the Astro E14 candle LED 4W 2700K dimmable (£13.80, checked 19 October 2026) gives 450 lumens through frosted glass and measures 98mm by 35mm, so check it clears your shade. The Endon Berenice wall light (£25.95, checked 19 October 2026) in the photograph at the top of this guide takes one E14 bulb of up to 6W, not included, and either of these suits it.
For reading, the colour matters less than getting enough light onto the page without a bright bulb in your line of sight. A shade that hides the lamp, placed where you actually sit, does more than a change of Kelvin. Our guide to layering a room covers where the lamps go once the colour is settled.
Kitchen: 3000K over the worktop
Our starting point is 3000K over the worktop, where you chop and read a recipe, with 2700K or 3000K over the table or the island seats, because by the evening that half of the room is a dining room. 4000K can suit a kitchen too if you prefer a neutral, crisp look. That is a preference, not a mistake. What matters more than the Kelvin figure is enough well-placed light on the worktop.
Keep 'bright' and 'cool' apart, because they are different things. Brightness is lumens. The LED GLS E27 12W 3000K clear bulb (£14.95, checked 19 October 2026) gives 1,521 lumens of warm white, exactly the same figure as its 4000K twin, so a warm kitchen does not have to be a dim one.
In an open-plan room, look at the lights you see together. Matching their colour temperatures makes the view more consistent, and putting the worktop lights and the table pendants on separate switches lets each do its own job. Two figures in one space can be a deliberate choice. If your worktop light is a run of GU10 downlights, check the Kelvin figure in the product details before you buy a set.
Bedroom: 2700K, on a dimmer if you can
The same logic as the living room: 2700K for the room, on a dimmer where the bulb, fitting and dimmer are compatible, with anything cooler kept to a dressing table or make-up mirror on its own switch. We wrote the bedroom up separately in what colour temperature is best for a bedroom.
Bathroom: 3000K overhead, around 4000K at the mirror
For the ceiling, 3000K is our starting point: clean without being cold. At the mirror our preference is around 4000K, with a colour rendering index, or CRI, of 90 or above where you can get it, on its own switch. A mirror is where you check skin tone, shave and do make-up, so a neutral appearance earns its place there, and the ceiling light does not have to do every job. That puts two figures in one room on purpose. It also agrees with our bathroom mirror lighting guide, which recommends 4000K to 5000K with CRI 90 or higher at the glass.
Kelvin and CRI measure different things. A 4000K bulb is not automatically good at showing colour, and a high CRI tells you nothing about colour temperature. The replacement bulbs we list state CRI 80 where they give a figure, so if CRI 90 matters at your mirror, check the specification of the mirror light itself. Our guide to CRI explains the number.
Where the light comes from matters more than either figure. A single light overhead casts shadows under the eyes and chin; light from the sides at face height reduces them. Colour temperature also says nothing about whether a fitting is suitable for its position in the room, so check the bathroom zone and IP rating as well.
Hallway, landing and stairs: match the rooms off them
Give a hall or landing the same figure as the rooms it joins, which in most houses means 2700K or 3000K. A cool white hall between two warm rooms is the first light a visitor sees, and to us it reads as a corridor. If the stairs need more light, add lumens or another fitting rather than Kelvin.
Home office and utility: where 4000K earns its place
A utility room, a garage, a workbench or a desk used by day is where we would happily fit 4000K, if you like a neutral look while you work. Compare 3000K and 4000K with the daylight the room gets. If the desk is also where you sit in the evening, a 2700K lamp beside it gives you a warmer option on a separate switch. Neither figure makes up for poor placement, too little light or reflections on a screen.
Outside: 2700K to 3000K on the house
Near the house our preference is 2700K to 3000K. A warm lantern by the front door looks like part of the house; a 5000K to 6000K floodlight, to our eye, turns brickwork grey. A security light does not have to be cool white to do its job: aim the beam at the area you need lit and use the controls it has. Our guide to outdoor wall lights covers the wider choice.
For a lantern with an E27 cap and clear glass where the bulb shows, the Candle E27 filament LED 2700K (£7.46, checked 19 October 2026) gives 470 lumens and dims, and the Vintage Tubular E27 LED 2700K (£12.95, checked 19 October 2026) gives 300 lumens from a 110mm tube. Same colour, different shape and output. Check the lantern's maximum wattage and whether its maker allows that bulb in an enclosed fitting before choosing either.
Can you mix warm white and cool white?
Between rooms, yes, and the kitchen and bathroom above are worked examples. Within one view, our preference is a single figure for the lights you see together, because one 4000K bulb among 2700K ones is easy to spot. A task light on its own switch, like a mirror light, is a different matter. When you replace one bulb, match the figure on the old one. If you cannot remember it, switch off, let the bulb cool, take it out and read it.
How do our bulb names map to Kelvin figures?
Buy on the stated Kelvin figure whenever an exact match matters. Most of our product pages give it in the details table as LED Colour Temperature. The Astro GU10 LED 4.1W 2700K dimmable (£8.76, checked 19 October 2026) states 2700K and 500 lumens, and one reviewer found it 'dims right down to nothing' without flicker on their dimmer. The G9 LED bulb 3.7W Natural White 4000K dimmable (£6.47, checked 19 October 2026) states 4000K and 470 lumens. Neither cap tells you the colour; the specification does.
A few of our warm white listings do not give a precise figure, and on a few the title, the description and an older web address disagree. If you find that, ask us to confirm the bulb before you buy a set, and never treat a web address as a specification. The names trip people up too: one review of our 4000K G9 capsule says it was expected to be soft white and turned out cool white. Read the number, not the adjective.
Is cool white brighter than warm white?
Not necessarily. Brightness is lumens, and our 12W GLS bulbs above list 1,521 lumens at 3000K and at 4000K. Colour can change how bright a room feels to you, but the Kelvin figure is not a brightness scale. If a room needs more light, buy more lumens and keep the colour you like. On a colour-switchable bulb, check whether the stated output changes between settings. Our guide to dimming LEDs covers turning it down again.
Which is better for your eyes, warm white or cool white?
Kelvin alone does not decide comfort. We do not recommend a colour temperature as a treatment for eye strain, and we do not claim a health benefit for warm or cool white. What we can offer is practical: give the task enough light, keep a bright bulb out of your direct view with a shade or diffuser, and look for reflections. Then choose the colour you like for the room.
For a reading corner, try the lamp where you actually sit. If the page is hard to see, look at the light on the page, the shade position and any glare before you change the colour temperature.
What should you check before buying?
- The Kelvin figure. Our starting points: 2700K where you relax, 3000K over a worktop, around 4000K at a mirror or workbench.
- Lumens. That is the brightness. Compare it at the setting you will use.
- The cap. E14, E27, GU10 or G9; our E14 and E27 guide explains the screw caps.
- Size and wattage. The bulb must fit the shade and stay within the fitting's stated maximum.
- Dimming. The bulb must be dimmable and the dimmer compatible with it.
- One first. Where practical, try one bulb in the room before buying a set, and buy a set from the same range and specification if you want them to match.
For shape, quantity and running cost, see what bulbs your new light needs. The full light bulb range is sorted by cap.
The short version
- Our starting points: 2700K where you relax, 3000K over a worktop, around 4000K at a bathroom mirror, utility room or daytime desk.
- They are recommendations, not rules. A 4000K living room you like is not a wrong purchase.
- Kelvin is the colour of the light; lumens are the amount. Choose them separately.
- Names are not standardised: in our own range 'cool white' covers both 4000K and 6000K. Buy on the number.
- At a mirror, look for CRI 90 where you can get it. Kelvin and CRI measure different things.
- No colour temperature is a health treatment. Glare and too little light are the comfort problems to fix.
Frequently asked questions
Which is better, warm white or cool white?
Neither everywhere. We start at 2700K where you relax, 3000K over a kitchen worktop and around 4000K at a bathroom mirror, in a utility room or at a desk used by day. Those are our recommendations. If you prefer a different figure in a room, that is a matter of taste rather than a mistake.
Is 4000K cool white or daylight?
The names vary. 4000K is usually called neutral or natural white, and some bulbs, including a couple of ours, call it cool white. Daylight usually means 5000K and above. Compare the Kelvin figure rather than the name.
Should I choose 2700K or 3000K?
2700K gives the warmer appearance and is our default for living rooms and bedrooms; 3000K is a little crisper and is where we start over a kitchen worktop. Both can work in living spaces, so try them with your own decor and the other lights in the room.
Is 3000K or 4000K better for a kitchen?
We would start at 3000K over the worktop, because it is crisp enough to work under and warm enough for a room that is also lived in. 4000K suits a kitchen if you like a neutral look. Enough light on the worktop matters more than either figure.
Should I use cool white or daylight bulbs in a kitchen?
In most kitchens we would use neither and start at 3000K. If you want a neutral look, 4000K is the step we would try before anything labelled daylight, which is usually 5000K or more.
Will a dimmer make cool white warm?
Not an ordinary dimmable LED: it gets less bright, it does not set out to change colour. Bulbs sold as dim to warm are made to shift warmer as they dim; Philips, for example, lists its WarmGlow spots at 2200K to 2700K. Look for that wording in the specification if you want it.
