I filed my taxes a couple days ago and did not add my car mileage deduction on my account. I updated it today, will it still be accepted with my update included?

[DawnC0 · Accepted solution]

Not if you already filed your return.  If you have already filed, you have to wait for the IRS to either accept or reject your tax return.  If rejected you can add your mileage deductions and re-submit.

If accepted, then you have to wait for the tax refund to be received or the taxes owed that were paid to be processed by the IRS.  Then you will have to file an amended tax return, Form 1040X, to add the deduction.  

Please note that car mileage is only deductible if you are self-employed.