Where do I see the tax benefit of HSA pre-tax contributions? W2 shows Code W in Box 12, but I don't see my tax burden reduced after entering it.

[dmertz · Accepted solution]

You get the immediate tax benefit by your employer having excluded the code W amount from the taxable amount shown in box 1 of your W-2.  You do not get to deduct it again on your tax return.  Had you not had some of your pay sent to the HSA, the amount in box 1 of your W-2 would have been higher and the taxable income reported on your tax return would have been higher.