What this lesson covers
How taxes work for small businesses — not as a substitute for an accountant (you need one), but as the knowledge required to make informed decisions throughout the year rather than scrambling at tax time. This lesson covers how each corporate structure is taxed, what’s deductible, how quarterly payments work, and how daily business decisions affect your tax bill.
Prerequisites
Small Business Bookkeeping and Choosing a Corporate Structure. Tax strategy depends on accurate records and entity type.
How small business income is taxed
Sole proprietorship / single-member LLC
All business profit flows to your personal tax return (Form 1040, Schedule C). You pay:
- Federal income tax at your marginal rate (10–37% depending on total income)
- Self-employment tax: 15.3% on net earnings (12.4% Social Security up to the annual cap + 2.9% Medicare). This is the combined employer and employee share — because you’re both.
- State income tax (if your state has one)
The self-employment tax is the most painful part. On 11,300 — before income tax.
Partnership / multi-member LLC
Same as sole proprietorship, but profits are split among partners according to the operating agreement. Each partner receives a Schedule K-1 reporting their share and pays taxes on their personal return. Each partner pays self-employment tax on their share (with some exceptions for limited partners).
S-Corporation
Profit flows through to the owner’s personal return (like an LLC), but with a key difference: the owner pays themselves a reasonable salary, which is subject to payroll taxes (15.3% combined employer + employee). Profit above the salary is taken as a distribution, which is subject to income tax but NOT self-employment/payroll tax.
Worked example:
| Sole proprietor | S-Corp owner | |
|---|---|---|
| Net business income | $100,000 | $100,000 |
| Reasonable salary | — | $60,000 |
| Distribution | — | $40,000 |
| Self-employment / payroll tax base | $100,000 | $60,000 |
| SE / payroll tax (15.3%) | $15,300 | $9,180 |
| Tax savings | — | $6,120 |
The “reasonable salary” must genuinely reflect what you’d pay someone to do your job. The IRS scrutinizes S-Corp owners who pay themselves 200,000 of income. Set it based on comparable wages for your role and industry.
C-Corporation
The corporation pays corporate income tax (21% flat federal rate) on its profits. When profits are distributed to owners as dividends, the owners pay individual income tax on the dividends (qualified dividends taxed at 0%, 15%, or 20% depending on income). This is “double taxation.”
For most small businesses, double taxation makes C-Corp status unattractive unless the business needs to retain significant earnings for growth (the 21% corporate rate may be lower than the owner’s personal rate) or investors require it.
Common deductions
A deduction reduces taxable income. A 240 in federal income tax (plus the self-employment tax savings if applicable).
Deductions every small business should know
| Deduction | What qualifies | Notes |
|---|---|---|
| Cost of goods sold | Ingredients, materials, direct labor | Subtracted from revenue to calculate gross profit — the largest deduction for most businesses |
| Rent | Commercial lease payments | Fully deductible |
| Wages and salaries | Employee compensation | Includes employer’s share of payroll taxes |
| Insurance | Business insurance premiums | General liability, property, workers’ comp, etc. |
| Supplies | Office supplies, cleaning supplies, smallwares | Items used up within the year |
| Utilities | Electric, gas, water, internet, phone | Business portion only |
| Professional fees | Accountant, attorney, consultant | Must be ordinary and necessary for the business |
| Advertising and marketing | Ads, signage, website hosting, printed materials | Fully deductible in the year spent |
| Interest | Interest on business loans and credit | The interest portion of loan payments — not principal |
| Depreciation | Equipment, vehicles, leasehold improvements | Spread over useful life, or accelerated via Section 179 |
Section 179 and bonus depreciation
Normally, a 2,100–15,000 in the year of purchase (up to the annual limit, currently over $1 million). Bonus depreciation provides similar immediate deduction for qualifying assets.
This is powerful for new businesses with large equipment purchases. Instead of a 15,000 deduction in year one — when you probably need the tax reduction most. Discuss timing with your accountant.
Commonly missed deductions
| Deduction | What’s missed |
|---|---|
| Vehicle expenses | Mileage for business trips (deliveries, supplier visits, bank runs). Track mileage with an app — the IRS requires a log. Standard mileage rate or actual expenses, whichever is higher. |
| Home office | If you do administrative work from home (bookkeeping, ordering, planning), the portion of your home used exclusively for business is deductible. Simplified method: 1,500 max). |
| Startup costs | Up to $5,000 in startup expenses (market research, travel to find a location, training before opening) can be deducted in year one. The remainder is amortized over 15 years. |
| Education and training | Conferences, courses, books, and certifications related to the business |
| Bank and credit card fees | Monthly account fees, processing fees, merchant service charges |
| Software and subscriptions | POS software, accounting software, scheduling tools, industry subscriptions |
| Meals | Business meals (meeting with a vendor, traveling for business) are 50% deductible. Employee meals during shifts may be fully deductible as a de minimis fringe benefit — ask your accountant. |
Quarterly estimated taxes
If you expect to owe $1,000 or more in federal taxes for the year, you’re required to pay quarterly estimated taxes. Missing these payments triggers a penalty — even if you pay the full amount on April 15.
Due dates
| Quarter | Period covered | Due date |
|---|---|---|
| Q1 | January 1 – March 31 | April 15 |
| Q2 | April 1 – May 31 | June 15 |
| Q3 | June 1 – August 31 | September 15 |
| Q4 | September 1 – December 31 | January 15 (following year) |
How to calculate
Two safe methods (either avoids penalties):
- Prior year safe harbor: Pay 100% of last year’s total tax, divided into four equal payments (110% if your adjusted gross income exceeds $150,000).
- Current year estimate: Pay 90% of this year’s expected tax in four equal payments.
For a new business with no prior year, estimate conservatively. It’s better to overpay (you’ll get a refund) than to underpay (penalty plus a large April surprise).
Practical approach
Ask your accountant to calculate your quarterly amounts after the first full quarter of operation. Once established, set calendar reminders and transfer the payment amount to a separate savings account each month (one-third of the quarterly amount) so the money is available when due.
Sales tax
If your state has sales tax and you sell taxable goods, you are a tax collector — collecting from customers and remitting to the state.
What you need to know
- What’s taxable: Varies by state. Most states tax prepared food; some tax groceries; a few tax neither. Beverages, alcohol, and packaged goods may have different rates.
- Collection: Your POS should calculate sales tax automatically based on your location and applicable rates.
- Remittance: File and pay on the schedule your state assigns (monthly, quarterly, or annually based on sales volume). Late filings incur penalties and interest.
- Trust fund liability: Sales tax collected from customers is not your money. It’s held in trust for the state. Using collected sales tax to cover operating expenses is a serious legal violation.
Keeping sales tax separate
Some business owners keep collected sales tax in a separate bank account, transferring it out only when remitting to the state. This prevents accidentally spending money that belongs to the government.
Tax planning throughout the year
Tax strategy is not an April activity. Decisions made throughout the year determine the tax bill.
Timing income and expenses
Under cash-basis bookkeeping, you can influence when income and expenses are recognized:
- Deferring income: If December is a strong month and you expect lower income next year, delaying invoices until January pushes that revenue into the lower-income year.
- Accelerating expenses: If you need supplies or equipment, buying in December rather than January moves the deduction into the current year.
- Section 179 timing: If you’re planning a major equipment purchase, buying before December 31 lets you deduct it this year.
These are legal timing decisions, not evasion. Discuss with your accountant based on your specific situation.
Entity review
Review your corporate structure annually with your accountant. A business that started as a sole proprietorship may benefit from S-Corp election once profits exceed 60,000. The savings compound each year.
Retirement contributions
Self-employed individuals and small business owners have access to retirement accounts that double as tax deductions:
| Account | Contribution limit (2025) | Who can use it |
|---|---|---|
| SEP IRA | Up to 25% of net self-employment income (max ~$69,000) | Sole proprietors, LLC members, S-Corp owners |
| Solo 401(k) | 69,000 combined) | Business owners with no employees (other than a spouse) |
| SIMPLE IRA | $16,000 employee + employer match | Businesses with ≤100 employees |
A 4,800 in federal income tax plus potentially 7,860 in tax savings while building retirement savings.
Guidance
- Calculate your effective tax rate: total taxes paid (income + self-employment + state) ÷ net business income. Is it what you expected?
- If you’re a sole proprietor or single-member LLC earning over $50,000, calculate the potential savings of an S-Corp election using the worked example above. Discuss with your accountant.
- Set up a system for quarterly estimated taxes: a recurring calendar event, a separate savings account funded monthly, and a relationship with an accountant who calculates the amounts.