HSA box 12 which number abc or d

[AnthonyC · Accepted solution]

Box 12 can have multiple items.  The "small" letters -12a, 12b, 12c, 12d  - refer to the line numbers inside box 12.  What you want to look for is box 12 (small letter a, b, c, or d) code W - code W refers to contributions made to your HSA.