A19 vs. A21 LED Light Bulbs

When you think of a light bulb, you probably have an incandescent A19 pictured in your head. Standard light bulbs are A19s–the "A" referrs to the shape of the bulb and the "19" refers to the 19/8" (2.375") diameter. With the growing LED industry, manufacturers have designed a bigger A21 bulb to help disperse heat in high wattage LEDs. An A21 bulb has a 21/8" (2.625") diameter and a slightly longer neck. A21s are usually 13+ watt LEDs, which are equivalent to 75+ watt incandescent light bulbs. Most fixtures can accommodate both A19s and A21s, but be sure to check before purchasing an A21!