Why does amended return line 1 go up by $6,416 when I amend to add an IRA RMD 1099-R for only $3,467.97 (with $762.95 taxes withheld on RMD)?

[SweetieJean · Accepted solution]

Do you also collect Social Security?  More of it may have become taxable as a result of the increase in (other) income.

[dmertz]

Line 1 going up by 1.85 times $3,468 indeed indicates that this RMD income indeed increased taxable Social Security income by $2,948.