S-Corp vs LLC for New Engineering Firms: Which Saves More on Taxes?
Compare S-Corp vs LLC tax savings for new engineering firms. See real numbers, steps to choose, and FAQ. Make the right call for your practice.
For a new engineering firm, the choice between an S-Corp and an LLC often comes down to tax savings. The short answer: an S-Corp typically saves more on self-employment taxes once your net profit exceeds about $40,000 per year, but an LLC offers simpler administration and more flexibility. This guide breaks down the numbers, the trade-offs, and the steps to decide.
How LLCs and S-Corps Are Taxed Differently
A single-member LLC is taxed as a sole proprietorship by default. You report business income on Schedule C of your personal tax return, and you pay self-employment tax (Social Security and Medicare) on the entire net profit. In 2026, the self-employment tax rate is 15.3% (12.4% for Social Security up to the wage base of $176,100, plus 2.9% for Medicare with no cap).
An S-Corp is a corporation that elects pass-through taxation. You must pay yourself a “reasonable salary” as an employee, and that salary is subject to payroll taxes (Social Security, Medicare, and unemployment). Any remaining profit is distributed to you as a shareholder, and those distributions are not subject to self-employment tax. The trade-off: you must run payroll, file additional forms, and adhere to strict deadlines.
The Tax Savings: Real Numbers for 2026
Let’s compare a single-owner engineering firm with $120,000 in net profit (after business expenses but before owner compensation).
- LLC (sole proprietorship): You pay self-employment tax on the full $120,000. That’s $120,000 × 15.3% = $18,360. Plus income tax on the full amount.
- S-Corp: You set a reasonable salary of $80,000 (a common range for a working engineer). Payroll taxes on $80,000: Social Security (6.2% employer + 6.2% employee = 12.4%) = $9,920, plus Medicare (1.45% + 1.45% = 2.9%) = $2,320, total payroll taxes = $12,240. The remaining $40,000 is a distribution, with zero self-employment tax. Total payroll tax: $12,240.
That’s a savings of $6,120 per year in payroll taxes alone. However, you’ll also have additional costs: payroll service fees (about $40-$60 per month), state fees (varies, often $100-$500 per year), and possibly a CPA for the extra filing. Even after those costs, the S-Corp can save $4,000-$5,000 annually at this profit level.
But the break-even point matters. At $40,000 net profit, the S-Corp savings are minimal, and the administrative costs may eat them up. At $30,000, an LLC is usually cheaper.
Comparison Table: LLC vs S-Corp for New Engineering Firms
| Factor | LLC (single-member) | S-Corp |
|---|---|---|
| Setup cost | $50-$200 (state filing) | $100-$300 (state filing + articles) |
| Annual fees | $0-$100 (state franchise tax) | $100-$500 (franchise tax varies by state) |
| Payroll costs | $0 (no payroll required) | $40-$60/month for payroll service |
| Tax filing complexity | Simple (Schedule C) | Moderate (1120-S + payroll reports) |
| Self-employment tax on all profit | Yes | No (only on salary) |
| Profit distributions | Not applicable | Tax-free (no self-employment tax) |
| Reasonable salary requirement | No | Yes, must be market rate |
| Best for net profit | Under $40,000 | Over $40,000 |
When an LLC Makes More Sense
If your engineering firm is just starting and you expect to net less than $40,000 in the first year or two, an LLC is the practical choice. You avoid payroll setup, quarterly payroll tax deposits, and the risk of an IRS audit for unreasonable salary. You can also change to an S-Corp later without penalty, as long as you meet the eligibility requirements.
LLCs also offer more flexibility in profit distribution: you can allocate profits differently among members, which is useful if you have partners with different capital contributions. An S-Corp requires distributions to be proportional to ownership percentage.
When an S-Corp Saves More
Once your net profit exceeds $40,000, the S-Corp starts to pay off. For an engineering firm with $150,000 in net profit, the savings can be $7,000-$8,000 per year. Over five years, that’s $35,000-$40,000, which is significant for a growing practice.
To make it work, you must set a reasonable salary. For a licensed engineer in 2026, reasonable salaries range from $70,000 to $110,000 depending on location and experience. The IRS looks at factors like your role, billable hours, and industry norms. If you pay yourself too little, you risk penalties and back taxes.
Practical Steps to Decide This Week
- Estimate your net profit for the next 12 months. Use a conservative number: take your projected revenue minus all business expenses (software, equipment, insurance, marketing, etc.).
- Calculate the tax savings using the formula: (Net profit - reasonable salary) × 15.3%. Compare that to the added costs (payroll service, state fees, CPA).
- Check your state’s rules on S-Corp taxation. Some states, like California, impose a 1.5% franchise tax on S-Corp net income, which reduces the benefit. Others, like Nevada, have no corporate income tax.
- Talk to a CPA who works with engineering firms. They can run the exact numbers for your situation and help you set up payroll if you choose an S-Corp.
- If you’re leaning S-Corp, file Form 2553 with the IRS. You must file within 2 months and 15 days of the start of the tax year, or by the 15th day of the third month of the fiscal year. For a new entity, you can elect S-Corp status when you incorporate.
Frequently Asked Questions
Can I switch from an LLC to an S-Corp later? Yes. You can elect S-Corp status by filing Form 2553 with the IRS. The election must be made no later than 2 months and 15 days after the start of the tax year in which you want it to take effect. You’ll also need to update your state registration and start payroll.
What is a reasonable salary for an engineer in an S-Corp? For 2026, reasonable salaries for engineers range from $70,000 to $110,000, depending on your specialty, location, and experience. The IRS looks at what you would pay an unrelated employee to do the same job. Keep records of industry salary surveys to justify your number.
Are there any downsides to an S-Corp besides payroll? Yes. You must file a separate corporate tax return (Form 1120-S), which adds accounting fees. You also face stricter compliance: shareholder meetings, minutes, and corporate formalities. And if you miss payroll deadlines, you can face penalties.
What if I have multiple owners? Both LLCs and S-Corps can have multiple owners. LLCs allow flexible profit sharing, while S-Corps require distributions proportional to ownership. S-Corps are limited to 100 shareholders, and all must be U.S. citizens or residents.
The Bottom Line
For a new engineering firm, the tax savings from an S-Corp become real once your net profit exceeds $40,000. Below that, an LLC is simpler and cheaper. Above that, the S-Corp can save you thousands each year, but only if you set a reasonable salary and manage payroll correctly. Start by estimating your profit, run the numbers, and consult a CPA. The right choice depends on your specific revenue, state, and growth plans, so make the decision based on your actual numbers, not a generic rule of thumb.