Massachusetts charges 5% flat + 4% surtax >$1M state income tax. Use the side income tax calculator pre-loaded with Massachusetts rates.
Open Side Income Tax Calculator →Side income in Massachusetts is subject to federal income tax at your marginal rate, self-employment tax if applicable, and a flat 5% Massachusetts state income tax. Because side income typically stacks on top of your W-2 salary, it is often taxed at your highest marginal rates. The combined marginal rate on side income can easily exceed 40% for mid-to-high earners. This calculator breaks down exactly what you keep from each dollar of side income in Massachusetts.
Massachusetts levies a flat 5% state income tax on all taxable income regardless of how much you earn. This makes tax planning straightforward: for every additional dollar you earn, 5 cents goes to Massachusetts. Massachusetts does not impose local income taxes, so the 5% flat rate is the only state-level income tax you owe.
The table below shows what you actually keep at five salary levels in Massachusetts, accounting for federal tax, FICA, and Massachusetts's flat 5% state tax.
See how Massachusetts compares to other Northeast states. Each link takes you to the side income tax calculator landing page for that state.
For a comprehensive breakdown of Massachusetts’s tax structure, salary comparisons, cost-of-living analysis, and more, visit the full Massachusetts take-home pay page.