Standard vs Itemized Deductions

Filing single, no dependants, $0 income.

 

“Your standard deduction is $12,400 and your itemized deduction is $0. Since your standard deduction is more than or equal to your itemized deduction, we'll use it as your deduction.”

 

Just confused as to why the deduction would be $12,400 when no deductions were made ?

 

When using the non-filers in 2019, the deduction was $0. Why won’t it allow it to be $0 in 2020 when using TurboTax?