What this calculator does
Massachusetts voters approved the Fair Share Amendment in 2022, adding a 4% surtax on taxable income above $1 million, adjusted for inflation. For 2026 the threshold is $1,107,750. This calculator shows how much of your income is subject to it and your total Massachusetts tax.
How to use it
- Enter taxable income (wages, business income, gains).
- Choose filing status — joint filers share one threshold.
- Enter any short-term capital gains, which Massachusetts taxes at 8.5%.
The formula
Base tax = (income − personal exemption) × 5%. Surtax = (taxable income − $1,107,750) × 4% if positive. Short-term gains add 3.5% more than the 5% base rate in this estimate.
Worked example
Using the default inputs shown in the calculator above:
| Item | Amount |
|---|---|
| Total income | $1,500,000 |
| Personal exemption | -$4,400 |
| Taxable income | $1,495,600 |
| 5% on all taxable income | $74,780 |
| Surtax threshold (2026) | $1,107,750 |
| 4% on income above the threshold | $15,514 |
| Short-term gains: extra 3% (8.5% rate vs 5%) | $0 |
| Total | $90,294 |
Estimated 4% surtax: $15,514. On $387,850 of income above $1,107,750.
Only the income above $1,107,750 pays the extra 4%, so the top rate becomes 9% on that slice while everything below stays at 5%. Spreading a large gain over two tax years can lower the surtax.
Who pays the surtax
Most surtax payers have a one-time event: selling a business, exercising stock options or selling a home with a large gain. Because married couples share one threshold, some high-earning couples consider filing separately; that choice has other trade-offs. The revenue is dedicated to education and transportation.
Surtax at different income levels
The table shows a single filer with ordinary income and the $4,400 personal exemption, using the $1,107,750 threshold for 2026. Short-term capital gains, which Massachusetts taxes at a higher rate, are left out to keep the comparison simple.
| Total income | 5% base tax | 4% surtax | Total MA income tax | Effective rate |
|---|---|---|---|---|
| $1,000,000 | $49,780 | $0 | $49,780 | 4.98% |
| $1,250,000 | $62,280 | $5,514 | $67,794 | 5.42% |
| $1,500,000 | $74,780 | $15,514 | $90,294 | 6.02% |
| $2,000,000 | $99,780 | $35,514 | $135,294 | 6.76% |
| $3,000,000 | $149,780 | $75,514 | $225,294 | 7.51% |
| $5,000,000 | $249,780 | $155,514 | $405,294 | 8.11% |
Even at $5 million of income, the effective Massachusetts rate stays below 9%, because the first $1.1 million or so is taxed only at 5%. The surtax most often catches people in a single unusual year, such as the year they sell a business, exercise stock options or sell a home with a large gain that is not excluded.
Common mistakes and tips
- Assuming it applies to all income — only the part above the threshold.
- Forgetting capital gains count toward the threshold.
- Missing estimated payments after a large one-time gain.
- Assuming the threshold doubles for joint filers — it does not.
Frequently asked questions
What is the Massachusetts millionaire tax threshold for 2026?
$1,107,750 of taxable income.
Is the surtax on all income or only the excess?
Only on income above the threshold.
Do joint filers get a double threshold?
No. Married couples filing jointly share one threshold.
Does selling a home trigger it?
A taxable gain on a home sale counts toward income, so a large gain can push income over the threshold in that year.
Sources
Disclaimer
This calculator provides estimates for educational purposes only and is not financial, tax, legal, real estate, or insurance advice. Consult a licensed professional before making decisions.