If you feel TurboTax has made an error, we guarantee our calculations are 100% accurate. First, try to determine if the error and any penalty/interest is due to a calculation error. You can then follow the instructions below to submit a claim under our 100% Accurate Calculations Guarantee.
You might be able to find discrepancies by comparing the line numbers and their corresponding values on the
PDF copy of your tax return
that you saved.
https://turbotax.community.intuit.ca/replies/2647678