[lotsofpulp]

Freefile on irs.gov and the pdf of the 1040 instructions. Just because some software validates doesn't release you from the liability, so if you actually have a complicated situation, I'd find a qualified tax professional or read through the myriad IRS rules and regs.

[e40]

Does this do validation?

[lotsofpulp]

I’m not sure what validation means, but it does auto calculate and tell you if things don’t add up.