TurboTax dividends and capital gains tax rate not matching up

[sh00zkosmosu]

Hello

When i add $1610 in qualified dividends (1099-DIV 1b = 1610$) in web TurboTax my federal tax liability rises by $292 and state (IL) by $79. I do not understand where these numbers are coming from - according to my research dividends should be taxed @ 15% (i'm being taxed around 18%) and IL should not tax dividends (and it is taxing me 5%).  

Similar situation with capital gains on stocks. When i add sales of ESPP sales with adjusted cost basis (1099 Supplemental form) my total gain or loss is calculated @ $4056.31, but my Federal Tax Due raises by $808 and IL tax by $201. While IL number matches (4.95% of $4056.31 = $201). My Federal tax should be 15% of $4056.31 = $608, while i'm being taxed over $200 more. All sales are long-term and reported as such. Married filling jointly, i'm well under $250 000 so i should not pay Net Investment Income Tax.

Can anyone help me understand these where these numbers are coming from?

[RaifH]

Are there other credits on your tax return that could be impacted by the increase in income? Many credits start to be phased out or eliminated once your income reaches a certain threshold. The same with certain deductions that are tied to your AGI, like medical expenses. You can check to see if any other numbers may be affected by previewing your 1040.

I am also not certain why Illinois should not tax the dividends. Are they from a state-sourced bond or mutual fund or a high impact business? 

To preview Form 1040:

1. Open or continue your return.
2. Select Tax Tools in the left menu (if you don't see this, select the menu icon in the upper-left corner).
3. With the Tax Tools menu open, you can then view your 1040 form: Select Tools. Next, select View Tax Summary in the pop-up, then Preview my 1040 in the left menu

[sh00zkosmosu]

I do not see any other credits on 1040 Preview other than standard deduction ($25,100) and 

Refundable child tax credit or additional child tax credit ($2,700)

[FangxiaL]

Even though qualified dividends and long-term capital gain do receive preferential tax treatment, but they are part of your taxable income. With the added qualified dividends and capital gain, now you have more taxable income taxed at your marginal rate (22%), that is possibly why you see your total tax increases by more than the 15%. 

@sh00zkosmosu