Massachusetts Tax Calculator 2026 Flat 5% Rate

Massachusetts taxes income at a single flat rate of 5%, regardless of how much you earn. Income above roughly $1,083,150 is also subject to a 4% surtax. That makes the state-tax side of the math simple — the harder part is usually the federal side, which is why this page runs both together: enter your numbers once and see your combined federal + Massachusetts tax, with 2025 vs. 2026 vs. 2027 shown side by side.

This calculator uses the same engine as the main US Tax Calculator — see our Methodology page for exactly where every figure comes from, and our Disclaimer for what this tool does not model (AMT, NIIT, EITC, local taxes, and more).