Why most quick estimates look better than reality
The simplest S corporation estimate compares two numbers: the self-employment tax a sole proprietor pays on all profit, and the FICA an S corporation pays on the owner's salary. The gap between them is real, but it is the gross saving, not the net one.
Commonly used online estimators leave out some or all of the following: the QBI deduction lost to salary, payroll provider and return preparation costs, any state-level costs, other household wages, and health insurance. Some fill the salary field with a fixed percentage of profit. For a Massachusetts owner, the omissions that matter most are the state's: the $456 minimum excise, PFML on the owner's wages and, where it applies, unemployment insurance.
None of this makes an estimate useless. It means the figure should be read as a starting point, with the missing lines named, rather than as a saving.
The inputs, and why each one is there
These are the facts a comparison needs, roughly in the order they matter. The first two are essential; the rest can start from sensible defaults but change the answer when they are known.
| Input | Why it matters |
|---|---|
| Expected net business profit, before any owner salary | Everything else is measured against it. It should come from reconciled books, not a bank balance. |
| Current setup: sole proprietor, single-member LLC, multi-member LLC, or already an S corporation | Sets the starting point: self-employment tax on Schedule C, a partnership return, or an existing payroll. |
| Proposed owner W-2 salary | Drives FICA, PFML, UI and the QBI reduction. It must be reasonable for the work; there is no percentage default in IRS guidance. |
| Filing status and other household W-2 wages | Other wages use up part of the Social Security wage base and move the Additional Medicare Tax threshold ($200,000 single, $250,000 married filing jointly). |
| Tax year, 2025 or 2026 | Switches the wage base ($176,100 or $184,500), the QBI thresholds and the PFML table. |
| Owner health insurance premiums | For a more-than-2% shareholder, premiums paid by the S corporation go in W-2 Box 1 but not the Social Security and Medicare boxes. |
| Number of covered individuals, and whether the business is family-owned | Decides whether PFML is 0.46% or 0.88% of wages, and whether family exemptions apply to PFML and UI. |
| Massachusetts total receipts band: under $6 million, $6 million to under $9 million, $9 million or more | Decides whether the S corporation pays only the minimum or non-income measure, or also 2.00% or 3.00% of net income. |
| Legal form: LLC or state corporation | Decides which annual report the Secretary of the Commonwealth requires; the fee should be checked on sec.state.ma.us, not assumed. |
| Added costs: payroll provider and extra return preparation | Real, recurring and specific to you; they belong in the comparison as your own figures. |
| Planned retirement contributions | Some retirement plan limits are tied to compensation, and an S corporation owner's compensation is the W-2 salary rather than the profit, so the salary choice can affect them. Best shown as a flag, not modeled. |
The outputs a comparison should show
A single "you save X" figure hides the assumptions. A useful result shows each line, so you can see which one is doing the work and challenge it.
- Self-employment tax on the current setup, next to FICA on the salary (both halves), federal unemployment tax on the first $7,000 of wages (2026 wage base), Massachusetts UI where it applies (2.42% of the first $15,000 for a new employer in 2026) and PFML
- The change in the federal QBI deduction, and its income-tax effect at your bracket
- Massachusetts: the $456 minimum excise, any entity-level excise at $6 million or more of receipts, and any change in annual report costs
- Payroll provider and return preparation costs, as entered
- A net estimated difference, shown as a range rather than a single number
- The break-even profit: the level at which the result flips from cost to saving
Flags, not numbers
Some things matter too much to leave out and are too individual to reduce to a line. A careful comparison raises them as flags for a conversation instead of folding them into the total.
- Massachusetts 63D pass-through excise: 5% of qualified income at the entity level, with a 90% credit to members; available only to S corporations and partnerships, and potentially useful where state taxes exceed the federal SALT cap ($40,000 for 2025, $40,400 for 2026)
- Massachusetts 63E excise, new for tax years beginning on or after 1 January 2026: 4% on a member's share above the 4% surtax threshold, elected on Form 63-ELT, irrevocable for the year
- The 4% surtax itself, if household income is near $1,083,150 (2025) or $1,107,750 (2026)
- A salary that looks low relative to profit and the work described
- The Form 2553 deadline for the year chosen: for calendar year 2027, 15 March 2027
- PFML rates for 2027, which had not been set when this page was checked; any 2027 figure is a placeholder until the Department of Family and Medical Leave publishes it
How the break-even works
The break-even is the profit at which the net difference crosses zero. Below it, the fixed costs of the election outweigh the employment tax saved; above it, the saving grows as profit rises faster than the salary.
It is not a fixed number. Change the salary and it moves. Add a spouse's wages near the Social Security wage base and it moves. Switch the payroll provider or the return preparation cost and it moves. That is why the break-even belongs in the output of a comparison built on your inputs, not in a headline.
Illustrative: for 2026, a single owner with $100,000 of profit and a $50,000 salary saves $6,480 of employment tax before costs. The $456 minimum excise, $230 of PFML, $363 of UI if covered, and a QBI deduction roughly $9,350 smaller all come out of that before any provider or preparation fee. The same inputs at $40,000 of profit and a $25,000 salary leave about $893 before those fees and the QBI effect.
Why the result is an estimate, not a promise
A comparison is only as good as its inputs. Profit next year is a forecast. The reasonable salary is a judgment the IRS can question. Payroll and preparation costs vary. Rates change: the Social Security wage base, the QBI thresholds and the PFML rate are all reset for 2027, and none of the 2027 figures had been published when this page was checked.
So an honest result says what it assumed, in writing, and treats the net figure as an estimate. Anyone who quotes you a saving before seeing your books is guessing.
Where we come in
We can run the comparison with your actual numbers, line by line, using the inputs above and your reconciled books, and give you the assumptions in writing so you can see what would change the answer. We give you a scope and a price in writing before anything starts.
Figures on this page were checked against the IRS and Massachusetts sources listed alongside on 28 Sep 2026. They change — confirm the current amount before relying on one.
General information for owner-led businesses, not advice for your specific situation. Tax and accounting rules change, and how they apply depends on facts particular to your business. Talk to us — or to another qualified professional — before acting on anything here.
