A USB lamp is a table lamp that either runs from a USB port or carries a USB socket of its own for charging your phone. Either way, the point is the same: one less adaptor on the bedside table or desk, and sometimes no need for a spare wall socket at all.
The label hides three quite different designs, though, and picking the wrong one is the most common disappointment. A lamp that charges your phone is not necessarily a lamp you can take into the garden.
USB-powered. The lamp draws 5 V through its cable from a plug-in charger, a laptop, a monitor or a power bank, and goes out the moment you unplug it. These are usually small LED desk and reading lamps of roughly 1–5 W.
Rechargeable over USB. A built-in battery is topped up by USB, after which the lamp works cordless for an evening or several. This is the type people mean when they search for a cordless lamp for a sideboard, a dining table or a terrace; we cover it in more depth under cordless table lamps.
Mains lamp with a USB charging port. An ordinary mains table lamp with a USB-A or USB-C socket built into the base, the switch or the cord. The lamp itself doesn’t depend on USB; the port is there for your phone, tablet or earbuds. Some bases have a wireless charging pad instead of, or as well as, a socket.
This is the variant most UK buyers are after, and for good reason. Most bedside tables have one double socket shared by the lamp, the phone charger and perhaps an alarm clock. A lamp with a built-in port frees one of those outlets and keeps the phone within arm’s reach overnight.
A few points worth checking before you buy:
A USB-powered lamp can only be as bright as its source allows. The table shows typical outputs and what they mean in practice.
| Power source | Typical output | In practice |
|---|---|---|
| USB 2.0 port on a laptop | 5 V / 0.5 A (2.5 W) | fine for a small clip-on or gooseneck reading light |
| USB 3.x port on a laptop | 5 V / 0.9 A (4.5 W) | runs most 3–4 W desk lamps |
| Plug-in USB-A charger | 5 V / 1–2.4 A (5–12 W) | the dependable choice for a lamp on all evening |
| USB-C charger | 5 V at up to 3 A (15 W) | plenty of headroom |
| Power bank | 5 V / 1–3 A | handy when travelling, though some switch off when the draw is very low |
As a rough guide, a 3–5 W LED desk lamp gives 250–450 lumens, while tiny flexible lamps often give under 200. A mains table lamp for a living room is usually 800 lumens or more, so treat a USB lamp as task or accent lighting rather than the main light in a room.
For a lamp you will read or work under every evening, brightness is only half the story. A colour rendering index (CRI) of 80 is a sensible minimum, and 90 or above makes a real difference for drawing, sewing or matching colours. Cheap dimming circuits can flicker – too fast to notice, but tiring over a long session – so a flicker-free claim is worth looking for. An opal diffuser or a shade that hides the LEDs cuts glare, and a long, thin USB cable can drop enough voltage to make a small lamp visibly dimmer.
Not all of them. Some only light up while plugged into a USB port; others have a battery that charges over USB and then works cordless. Mains lamps with a USB port are different again – they charge your devices, not themselves. Check whether the description mentions a battery.
Usually somewhere between 5 and 20 hours, depending on the battery and the brightness. At full output expect roughly a third of the figure quoted for the lowest setting, so compare the low-setting run times.
One that puts around 500 lux on the desk: typically 300–450 lumens from 40–50 cm above the page, an adjustable arm, a neutral 4000 K for concentration and a dimmer for evenings. A USB-powered lamp run from a charger meets this easily.
It will charge it at standard speed, which is plenty overnight. For quick top-ups during the day, look for a USB-C port with a stated higher output.
Yes, for small lamps. A stronger lamp may flicker or dim on an older USB 2.0 port, and it may go off when the laptop sleeps, as many laptops cut USB power in sleep mode.
Very little. A 4 W lamp on for four hours a day uses roughly 6 kWh a year, so running cost is not a reason to choose one lamp over another.
More on mains lamps in fabric, ceramic or glass, and other ways to power a lamp, under table lamps.
