https://incometaxmodeller.com/

The challenge for you:
To see how we can raise further revenue through changes in the Personal income tax rate schedule.
If there is a need to raise $3.38 billion more revenue from Personal Income Tax, how would you set the Personal Income Tax rate schedule for the various assessable income groups?
Target Additional Tax Revenue S$ billion
Current: 13.45 Scenario: ⇒ (Shortfall) / Excess
Gini The Income Tax Gini coefficient measures the extent to which the burden of personal income tax paid by individual taxpayers deviates from a perfectly equal distribution.  A lower income tax Gini coefficient (closer to 0) is the most progressive where most of the personal income tax is paid by the highest earners. A high income tax Gini (closer to 1) is less progressive where the burden of income tax falls more equally amongst all taxpayers, irrespective of their income. Gini The Income Tax Gini coefficient measures the extent to which the burden of personal income tax paid by individual taxpayers deviates from a perfectly equal distribution.  A lower income tax Gini coefficient (closer to 0) is the most progressive where most of the personal income tax is paid by the highest earners. A high income tax Gini (closer to 1) is less progressive where the burden of income tax falls more equally amongst all taxpayers, irrespective of their income.
Change the marginal tax rates at each band BELOW:
First $ of Chargeable Income Current Marginal Tax rate (Residents) Flexed
Marginal
Tax rate 		Current Gross Tax Payable Flexed Gross Tax Payable
S$ % % S$ S$
20,000 0.00 0 0.00
30,000 2.00 200
40,000 3.50 550
80,000 7.00 3,350
120,000 11.50 7,950
160,000 15.00 13,950
200,000 18.00 21,150
240,000 19.00 28,750 Current: by top 10%
280,000 19.50 36,550 by bottom 20%
320,000 20.00 44,550 Scenario: by top 10%
320,000+ 22.00     by bottom 20%
 
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