Tax Basics for Business
Taxes are the one business expense you cannot avoid — but you can understand them. Here's what every business owner needs to know about income tax, sales tax, payroll tax, deductions, and when to call an accountant.
The freelancer who owed $23,000 she did not have
In 2020, Sarah quit her marketing job and went freelance. She was good — really good. By December, she had earned $110,000 in her first year. More than her old salary. She felt unstoppable.
Then she did her taxes in April.
As an employee, taxes had been invisible. Her employer withheld federal income tax, state tax, Social Security, and Medicare from every paycheck. She never thought about it. As a freelancer, nobody withheld anything. Every client payment landed in her bank account in full, and she spent it like it was all hers.
It was not all hers. She owed $18,700 in federal income tax, $3,200 in self-employment tax (Social Security + Medicare), and $1,400 in state taxes. Total: $23,300. Plus a $1,200 penalty for not making quarterly estimated payments — a requirement she did not know existed.
Sarah had $4,000 in her checking account.
This story plays out thousands of times every year. The tax system is not designed to surprise you — but if you do not understand the basics, it will surprise you anyway.
The four taxes every business faces
1. Income tax — Tax on profits
Every business pays tax on its net income (revenue minus deductible expenses). The rate depends on your business structure and income level.
- Sole proprietors and single-member LLCs: Business income passes through to your personal tax return. You pay at your individual rate (10-37% federal, depending on income bracket).
- Partnerships and S-corporations: Income passes through to the owners' personal returns (pass-through taxation).
- C-corporations: Pay a flat 21% federal corporate income tax rate. Owners also pay tax when they receive dividends — this is the "double taxation" people talk about.
2. Self-employment tax — Social Security and Medicare
If you are self-employed, you pay both the employer and employee portions of Social Security (12.4%) and Medicare (2.9%) — a combined 15.3% on the first $168,600 of net self-employment income (2024 threshold). Employees only see half of this because their employer pays the other half. Self-employed people pay the full amount.
3. Sales tax — Tax on transactions
If you sell physical products (and in many states, digital products or services), you may need to collect sales tax from customers and remit it to the state. Rates vary by state and locality — from 0% (Oregon, Montana) to over 10% in some jurisdictions. This tax is not on your income; it is collected from the buyer and passed through to the government.
4. Payroll tax — Tax on employee wages
If you have employees, you withhold income tax, Social Security, and Medicare from their paychecks and remit it to the IRS. You also pay the employer portion of Social Security and Medicare, plus federal and state unemployment taxes (FUTA/SUTA). Payroll taxes are the most time-sensitive — late payments trigger immediate penalties.
There Are No Dumb Questions
"What is the difference between a tax deduction and a tax credit?"
A deduction reduces your taxable income. If you earn $100,000 and have $20,000 in deductions, you pay tax on $80,000. A credit reduces your actual tax bill dollar for dollar. A $1,000 tax credit saves you $1,000 in taxes — regardless of your income. Credits are more valuable than deductions because they directly reduce what you owe, not just what you are taxed on.
"Do I have to pay taxes on revenue or profit?"
Profit. You pay income tax on net income — revenue minus allowable deductions. If your business earned $200,000 in revenue and had $150,000 in deductible expenses, you pay tax on $50,000. This is why tracking expenses meticulously is not just good accounting — it directly reduces your tax bill.
Estimated quarterly taxes
If you expect to owe more than $1,000 in federal taxes for the year, the IRS requires you to make quarterly estimated tax payments. The due dates:
| Quarter | Income period | Payment due |
|---|---|---|
| Q1 | January - March | April 15 |
| Q2 | April - May | June 15 |
| Q3 | June - August | September 15 |
| Q4 | September - December | January 15 (following year) |
Notice: the quarters are not evenly split. Q2 only covers two months while Q3 covers three. This is an IRS quirk that has confused people for decades.
How to calculate estimated payments:
- Estimate your total annual income
- Subtract expected deductions
- Calculate the tax on the result (income tax + self-employment tax)
- Divide by four
- Pay each quarter using IRS Form 1040-ES (or online at irs.gov/payments)
Calculate the Tax Bill
25 XPCommon business deductions
Deductions reduce your taxable income, which reduces your tax bill. Here are the deductions every small business owner should know:
| Deduction | What qualifies | Common mistakes |
|---|---|---|
| Home office | Dedicated space used exclusively for business. Deduct proportional rent/mortgage, utilities, internet. | Must be exclusively for business — a desk in the living room where you also watch TV does not qualify |
| Vehicle expenses | Business-related driving. Standard mileage rate: $0.67/mile (2024) OR actual expenses (gas, insurance, maintenance). Choose one method. | Personal commuting is never deductible. Keep a mileage log. |
| Equipment & supplies | Computers, software, office furniture, tools. Under Section 179, you can deduct the full cost in the year of purchase (up to $1,220,000 in 2024). | Must be used primarily for business. A laptop used 50/50 for work and personal? Deduct 50%. |
| Professional services | Accountant fees, lawyer fees, business consulting, bookkeeping software. | Only deductible if related to the business — personal legal fees do not count. |
| Health insurance | Self-employed individuals can deduct 100% of health insurance premiums for themselves and their family. | Cannot also claim the premium tax credit on the exchange for the same premiums. |
| Retirement contributions | SEP-IRA (up to 25% of net earnings), Solo 401(k) (up to $23,000 employee contribution + 25% employer contribution). | Contributions must be made by the tax filing deadline. |
| Education & training | Courses, conferences, books, and subscriptions related to your business. | Must be related to your current business — you cannot deduct law school as a freelance designer. |
There Are No Dumb Questions
"Can I deduct meals and entertainment?"
Business meals where you discuss business with a client, partner, or prospect are 50% deductible. Entertainment (sports tickets, concerts) is generally not deductible since the 2017 Tax Cuts and Jobs Act eliminated it. Keep receipts and note who you were with and what business was discussed — the IRS requires documentation for meal deductions.
"What about the standard deduction?"
The standard deduction ($14,600 for single filers, $29,200 for married filing jointly in 2024) is a personal tax deduction — it does not affect business deductions. You claim business deductions on Schedule C (for sole proprietors), and then you also get either the standard deduction or itemized deductions on your personal return. Business deductions and personal deductions are separate systems.
Record-keeping: what to keep and for how long
The IRS can audit returns from the past three years (six years if they suspect significant underreporting). Keep these records for at least that long:
Keep for 3 years minimum:
- Bank statements and credit card statements
- Receipts for all business expenses over $75
- Invoices sent and received
- Mileage logs
- Payroll records
Keep for 7 years (recommended):
- Tax returns and all supporting documents
- Contracts and agreements
- Employment records
- Depreciation schedules
Keep permanently:
- Business formation documents (articles of incorporation, LLC operating agreement)
- Property records
- Annual financial statements
Find the Deductions
25 XPWhen to hire an accountant
You do not need an accountant to track income and expenses — software handles that. But there are clear trigger points where professional help pays for itself:
Hire a tax preparer (CPA or Enrolled Agent) when:
- Your total income exceeds $75,000/year
- You have employees
- You are deciding between business structures (LLC vs. S-corp vs. C-corp)
- You are taking deductions you are not confident about
- You have been notified of an audit
Hire a bookkeeper when:
- You spend more than 5 hours/month on bookkeeping
- Your transaction volume exceeds 100 per month
- You are consistently behind on reconciling accounts
- You are making errors that your accountant has to fix at tax time
The cost of professional help:
- Bookkeeper: $200-500/month for a small business
- Tax preparation (sole proprietor): $500-1,500/year
- Tax preparation (S-corp or partnership): $1,000-3,000/year
- Full-service accounting (bookkeeping + tax + advisory): $500-2,000/month
A good accountant typically saves you more in taxes than they charge in fees. The S-corp election alone can save a $150,000/year freelancer $10,000-15,000 in self-employment taxes — far more than the accountant costs.
Business structures and tax implications
| Structure | How income is taxed | Self-employment tax? | Key advantage |
|---|---|---|---|
| Sole proprietor | Personal return (Schedule C) | Yes — 15.3% on all net income | Simplest, cheapest to set up |
| Single-member LLC | Same as sole proprietor (default) | Yes — 15.3% on all net income | Liability protection, same tax treatment |
| S-corporation | Salary + distributions on personal return | Only on salary, not on distributions | Saves self-employment tax on distributions |
| C-corporation | Corporate rate (21%) + dividends taxed personally | No — but double taxation on dividends | Best for reinvesting profits in the business |
| Partnership / Multi-member LLC | Pass-through to partners' personal returns | Yes for general partners | Flexible profit-sharing among partners |
The S-corp election is the most common tax optimisation for profitable freelancers and small business owners. Once your net income exceeds roughly $60,000-80,000/year, paying yourself a "reasonable salary" and taking the rest as distributions can save thousands in self-employment tax.
Key takeaways
- Four taxes affect businesses: income tax (on profits), self-employment tax (Social Security + Medicare for self-employed), sales tax (on transactions), and payroll tax (on employee wages).
- Self-employed people must make quarterly estimated payments. Missing them triggers penalties. Save 25-30% of every payment for taxes.
- Deductions reduce taxable income. Track every business expense — home office, vehicle, equipment, professional services, health insurance, retirement contributions.
- Keep records for at least three years (seven is safer). Use accounting software. Photograph receipts. The IRS accepts digital copies.
- Hire a professional when the complexity exceeds your confidence. A good CPA saves more in taxes than they charge in fees.
- Business structure matters for taxes. An S-corp election can save thousands in self-employment tax for profitable businesses.
Knowledge Check
1.A freelancer earned $110,000 and made zero estimated tax payments during the year. What consequence should they expect beyond the tax bill itself?
2.What is the self-employment tax rate, and who pays it?
3.A freelancer uses 20% of their apartment exclusively as a home office. Their rent is $2,000/month. What is the annual home office deduction?
4.Why might a profitable freelancer earning $150,000/year benefit from electing S-corporation status?