Why is the standard deduction calculating at 7215 instead of the 12000?

Are you being claimed as someone else's dependent?

 The standard deduction amount for an individual who may be claimed as a dependent by another taxpayer cannot exceed the greater of $1,100 or the sum of $350 and the individual’s earned income (not to exceed the regular standard deduction amount).

This is the only question you have posted under this username.  Are you a dependent?  

The Standard Deduction for an individual for whom an exemption can be claimed on another person's tax return is limited to the greater of:

…..$1,100 or

…..Your earned income for the year + $350 (but not more than 12,400)

So you would get a minimum of $1,100.

See the 1040 worksheet on page 32

https://www.irs.gov/pub/irs-pdf/i1040gi.pdf

Or Re you filing Married filing Separate?