My employer contributes $1,000 to my HSA and I contribute $5,750. On my W2 the total of $6,750 shows in box 12a as code W (employer contribution).

[BMcCalpin · Accepted solution]

The IRS considers any contribution from your employer AND any contribution to your HSA by means of payroll deduction to be "employer contributions". TurboTax has to use the same terminology. Therefore, it is correct that the sum of both amounts should be in box 12 with code W on your W-2.

The IRS does this because both amounts are treated the same way - that is, the total "employer contributions" are removed from boxes 1, 3, and 5 on your W-2. This is how your HSA contributions both from your employer and through your payroll deductions avoid being taxed.

If you were to make a contribution to your HSA outside of your employer, this is called a "personal contribution" and would appear on line 12 on Schedule 1 (1040)...but your payroll deductions should not appear on line 12, because they were never reported in your Wages in the first place.

[Edited 3/26/2020 10:20 am CDT - updated for 2019]