Why is the agi for 2017 different on my tax returns when I try to enter it for my 2018 taxes

[VolvoGirl]

Different where?

[LinaJ2018]

If you filed with TurboTax or have an original copy of 2017 tax return, locate the amount here   2017 AGI .

Or 

The best and fastest way to access the 2017 AGI is to order a transcript from the IRS.  Click here  Get Transcript and select "Get Transcript Online " On the transcript, look under section "Adjustment to Income" and find the amount for Adjusted Gross Income.