Washington update (effective 2028)
Washington has enacted a 9.9% tax on certain high-income individuals beginning in 2028. The tax base starts with federal AGI, subtracts long-term capital gains and adds back Washington capital gains subject to chapter 82.87 RCW, then applies a $1,000,000 deduction (single) / $1,000,000 combined (married/domestic partners).
Because QSBS gain excluded under IRC §1202 is excluded from federal AGI and is exempt from Washington’s capital gains excise tax to that extent, this calculator models §1202 excluded QSBS exits as not subject to the Washington millionaires tax. As administrative guidance evolves, confirm your treatment with a qualified tax advisor.