MR16 vs. GU10 bulbs

September 12, 2023

Find out the difference between the Philips Hue MR16 bulb and GU10 bulb, which you should choose, and how you can use them around your home.  

These two superheroes of lighting are compact and great at directing light exactly where you need it. But what is the difference between MR16 and GU10 bulbs?

MR16 and GU10 bulbs are both technically MR16 bulbs. One has a GU10 type base and the other has a GU5.3 type base. The bulb with a GU5.3 base has simply become known as an “MR16 bulb.” The bulb with a GU10 base is commonly referred to as exactly that: “a GU10.” Here, we’ll refer to the two bulbs as MR16 and GU10.

MR, which stands for “multifaceted refractor,” refers to the shape and design of the top part of the bulb. The number after MR refers to the diameter of the bulb in terms of eighths of an inch — the 16, in this case, means that the bulb is 16/8 inches (or 2 inches) in diameter.

GU, which stands for “general use,” refers to the base, or fitting, of the bulb. The number after GU refers to the spacing between the pins. GU10 has 10 mm spacing, while GU5.3 has 5.3 mm spacing.  

Today, MR16 bulbs and GU10 bulbs are commonly used in kitchens, hallways, and living rooms — typically as part of a track lighting setup, in spotlights, or recessed ceiling lighting.  

So, does it matter which one you use? At first glance, the two bulbs seem identical — but it’s important to choose the right one. 

Many existing MR16 bulbs are halogen bulbs, which are older and less energy efficient than LED bulbs. If you have older spotlight or track lighting setups with halogen bulbs, it’s possible that these are MR16 fittings. Look more closely and you’ll see that MR16 bulbs use a 12-volt, bi-pin base — two thin prongs that you simply push in. 

Another telltale sign of an MR16 setup is that it uses a 12 V transformer. This is the fundamental difference between GU10 and MR16 bulbs, and the most important thing to consider when upgrading your home lighting. A standard GU10 bulb will not work with this setup — you’ll need an MR16 bulb.

If you want to upgrade these older bulbs to MR16 smart light bulbs, Philips Hue has the answer. The new MR16 smart bulb is the ideal solution for your existing MR16 fittings. They work on the same 12 V low voltage as standard MR16 bulbs— so you won’t have to remove or replace your existing transformer. You can see which transformers Philips Hue smart MR16 bulbs are compatible with here.

Philips Hue MR16 smart bulbs are as bright as a 35 W halogen bulb, so they're the perfect smart upgrade from conventional bulbs (and with color light, they’re even more of an upgrade). They’re also just like any other Philips Hue bulb — smart. Add it in the Hue app, assign to a Room, and control with the app, your voice, or smart accessories.

Unlike MR16 bulbs, GU10s run on 240 V, which is the same as your home’s electricity. This means you don’t need a transformer to convert voltage. GU10 smart bulbs can be used in their respective light fittings, which include track lighting, spotlights, and recessed ceiling lighting. 

The GU10 light bulb from Philips Hue also offers all the smart lighting benefits you’d expect — app control, automations, and millions of colors of light. You’ll notice that GU10 bulbs are slightly smaller in diameter than MR16 bulbs, with a diameter of 50 mm. They also have a twist-and-lock base, recognizable by what look like two little “feet” that lock the bulb into position.

MR16 and GU10 bulbs are not interchangeable due to their size and voltage requirements. Your choice will depend on your existing light fittings or the ones you’re planning to install. 

Choose MR16 smart bulbs. It’s a simple question of upgrading your existing conventional MR16 bulbs to MR16 LED bulbs and you make them smart in the process!

It depends on what you would like to accomplish with your bulbs. Use GU10 fittings and bulbs for your ceiling, track, or spotlights if you want your bulbs to run on the standard 240 V and do not want to use a transformer. Transformers can take up extra space, depending on where you’re installing the lights. 

However, if you are concerned about the voltage, MR16 smart bulbs are a good option because the voltage is reduced. Whatever you choose, you can always use Philips Hue — both MR16 and GU10 bulbs are available in whatever color of light you want.