HOW DO I MEASURE MY LIGHT BULB?

​

Bulb sizing is very straightforward:

​

All bulbs are based on the diameter of the bulb at its widest point, measured in eighths of an inch (⅛”)

​

Some Examples:

​

The designation “T12” indicates a tubular bulb that measures 12 eighths of an inch (12/8”) in diameter (or 1-½” wide/around)

​

The designation “T8″ indicates a tubular bulb that measures 8 eights of an inch (8/8″) in diameter (or 1” wide/round)

​

The designation “T5″ indicates a tubular bulb that measures 5 eights of an inch (5/8”) in diameter 

​

The designation “Par38″ indicates 38 eights of an inch (38/8″) in diameter (or 4.75” wide)

​

The designation “A19″ of the most common household bulb indicates 19 eights of an inch (19/8″) in diameter (2-3/8” wide)