Estimate long-term capital-gains tax on an investment sale in Illinois.
Long-term capital-gains estimate in Illinois: gain above the cost basis taxed at the 0/15/20% federal LTCG brackets plus an optional state rate. Assets held under one year use income rates instead.
Gain
Gain = proceeds − basis; tax = gain × (fed + state)
Estimate only.
Then it is a short-term gain taxed at your ordinary income rate, often higher.
Rates are approximate reference values. Local rates, exemptions and rules can differ, so treat the output as a planning figure only.