Is a flickering LED bulb dangerous?

Occasional flicker is usually a compatibility issue rather than a hazard, but persistent flickering can point to a loose connection or an ageing dimmer. If it continues after trying a dimmable, LED-compatible bulb, have a qualified electrician check the fitting and switch.

Do all LED bulbs flicker?

No. A good-quality dimmable LED on an LED-compatible dimmer should not flicker. Flicker almost always comes from a mismatch between the bulb, the dimmer, or (for low-voltage spotlights) the transformer.

Last updated: 26 August 2026

Why do LED bulbs flicker?

Flickering (and its cousin, buzzing) is one of the most common LED complaints, and it almost always comes down to a mismatch — between the bulb or globe, the dimmer switch, or the transformer feeding a low-voltage spotlight. Often the flicker was there with your old bulbs too; the incandescent's warm, slow-fading filament simply hid it, and the LED reveals it. The good news is the cause is usually easy to pin down.

What causes an LED bulb to flicker?

A non-dimmable LED on a dimmer. The most common cause by far. Non-dimmable LEDs aren't designed to handle a dimmer's chopped power and will flicker, buzz or refuse to dim.
An old dimmer switch. Dimmers built for incandescent bulbs often can't smoothly control the tiny amount of power an LED draws.
A low-voltage MR16 transformer. Older transformers have a minimum load that a low-wattage LED can't meet, which causes flicker.
A loose connection in the fitting, or a very cheap bulb with a poor internal driver.

Leading-edge vs trailing-edge dimmers

This is the detail behind most dimmer flicker. Older dimmers use leading-edge switching — designed for the heavy load of incandescent bulbs, they chop the power in a way that an LED's tiny load handles poorly, producing flicker and buzz. Newer trailing-edge dimmers cut the power more gently and are made with LEDs in mind, so they dim smoothly and quietly. If your LEDs flicker on a dimmer even when the bulb is labelled dimmable, an old leading-edge dimmer is the likely reason.

Why does my LED flicker or glow when switched off?

A faint flicker or glow after you've turned the switch off is a slightly different problem: a tiny leakage current still reaching the bulb. It commonly comes from an illuminated or smart switch, a dimmer, or a long cable run picking up current from a neighbouring wire. LEDs need so little power to light up that this trickle is enough to make them glimmer. The reliable fix — a bypass or a change of switch — is electrical work for a qualified electrician, not a bulb swap.

MR16 and G9 spotlights

Low-voltage spotlights are the other classic flicker culprit. An MR16 runs through a transformer that may not be LED-rated; a G9 capsule is often on a dimmer or in a fitting with the same load-mismatch issue. In both cases, try a quality LED-rated globe first — and if the flicker stays, the transformer or dimmer is the part that needs an electrician's attention.

How to stop LED bulbs flickering

Start with the part you can safely do yourself: fit a bulb clearly labelled "dimmable" if it's on a dimmer, and choose a good-quality one — look for a recognised compliance mark (the RCM in Australia, UKCA or CE in the UK and Europe) and, ideally, a published dimmer-compatibility list. That alone solves many cases. If flicker continues, the switch or transformer is the likely culprit, and replacing a dimmer or fitting an LED-rated driver is electrical work for a qualified electrician. An electrician can fit a modern LED-compatible trailing-edge dimmer that dims smoothly.

Check your setup first

Not sure whether your bulb, dimmer and fitting are a good match? Our dimmer compatibility checker flags the risk and the fix in a few taps. If the bulb also looks wrong in other ways, try Fix My Bad Bulb.