GU10 vs MR16
GU10 and MR16 look nearly identical at a glance but run on different voltages — GU10 is mains voltage, MR16 is 12V. The pin shapes are also different.
Side-by-side specs
| Spec | GU10 | MR16 (GU5.3) |
|---|---|---|
| Voltage | Mains (120V / 240V) | 12V (low voltage) |
| Pin mechanism | Twist-lock (mushroom tips) | Push-in / retain (straight tips) |
| Pin spacing | 10 mm | 5.3 mm |
| Transformer needed? | No | Yes |
| Common fixtures | Downlights, recessed cans | Track with 12V transformer |
View on Amazon | View on Amazon
Can you substitute one for the other?
No. Wrong voltage, wrong pin dimensions, wrong locking mechanism. A GU10 will not seat in an MR16 holder and vice versa.
How to tell which you have
Look at the pin tips: GU10 pins have wide mushroom-shaped tips that click into the socket. MR16 (GU5.3) pins are straight thin wires that push straight in. If a GU10 bulb is in your hand, the pins wiggle side-to-side before locking — MR16 pins simply slide in.