What's the difference between a LED A19 bulb and a LED A21 bulb?
The main difference between these two bulbs is the number in the title which refers to their size. An A19 bulb is more of a standard household bulb, at 2.375 inches in diameter, and an A21 bulb is a little bit larger in length and width, at 2.625 inches in diameter, and sometimes do not fit in the same fixtures.