Why There Is a Range, Not One Number
Unlike W-2 executives who have taxes withheld automatically, fractional executives working as 1099 contractors or through their own LLC owe two separate tax buckets: self-employment tax and federal income tax. Self-employment tax is a flat 15.3% on net earnings (12.4% Social Security up to the annual wage base, plus 2.9% Medicare with no cap), calculated on Schedule SE. Federal income tax is progressive, so someone billing $120,000 a year in consulting fees sits in a different bracket than someone billing $400,000 across multiple retainers.
That is why 25% is a reasonable floor for someone with modest net income and significant deductions, while 35% is more realistic once combined federal and state marginal rates push past 24-32% on top of the SE tax. If you live in a state with income tax, add another 3-10% depending on the state.
Break the Number Into Two Real Buckets
Instead of guessing at one blended percentage, calculate the two pieces separately using your net income (revenue minus deductible business expenses reported on Schedule C):
- Self-employment tax: roughly 15.3% of net earnings up to the Social Security wage base for the current year, then 2.9% above it.
- Federal income tax: apply your expected marginal bracket to net income, keeping in mind the qualified business income deduction may reduce taxable income by up to 20% if you qualify.
Adding those two together usually lands between 25% and 35% for most consultants and fractional executives, but running your own numbers based on last year's actual net income is far more accurate than using a generic rule of thumb.
Handling the Famine Months
The hardest part of fractional work is not the percentage, it is the timing. Retainers get paused, projects end, and a great Q2 can be followed by a quiet Q3. Two habits fix this:
- Save on receipt, not on schedule. The moment a retainer or project invoice clears, move your target percentage into a separate tax savings account before you touch the rest. Do not wait until the quarterly deadline to figure out what you owe.
- Base quarterly payments on annualized income, not average income. Form 1040-ES estimated payments are due four times a year (mid-April, mid-June, mid-September, and mid-January), but the IRS allows you to use the annualized income installment method if your income is lopsided across the year. This prevents overpaying in a famine quarter based on a boom quarter's earnings.
Adjust as Your Rate Structure Matures
As your effective hourly or retainer rate climbs, your savings percentage should climb too, because more of your income falls into higher brackets. A consultant billing $150,000 a year might comfortably save 27%, while one billing $500,000 across three retainers may need closer to 35% once state tax and the loss of certain phase-out deductions are factored in. Revisit the percentage every time your annualized revenue changes materially, not just once a year at tax time.