Small Business Taxes: A Complete Guide for Business Owners

Last reviewed: August 2026

Running a small business means making dozens of financial decisions throughout the year—and many of them can affect your taxes.

Small business taxes aren’t just something to think about when it’s time to file a return. Your business structure, bookkeeping, payroll, purchases, estimated payments, deductions, and even the timing of certain decisions can affect what you owe and how smoothly tax season goes.

Understanding the basics can help you avoid unpleasant surprises, maintain better records, and have more productive conversations with your accountant or tax professional.

This guide covers the major tax issues small business owners should understand, including:

The main types of small business taxes
How your business structure affects taxation
Common business tax deductions
Estimated tax payments
Tax recordkeeping
Tax planning versus tax preparation
Year-end tax planning
Common tax mistakes
Wisconsin small business tax considerations
When to work with a tax professional
Frequently asked small business tax questions

Important: This guide provides general educational information and isn’t individualized tax, accounting, or legal advice. Tax rules depend on your business structure and circumstances and can change. Consult a qualified tax professional about your specific situation.

Understanding Small Business Taxes

There isn’t one single “small business tax.”

Depending on how your business is structured, where it operates, whether you have employees, and what you sell, you may have several different tax obligations.

Federal income tax

Business income is generally subject to federal income tax, but who pays the tax and how it is reported depends on the business structure.

Sole proprietorships and many pass-through businesses generally report business income through their owners’ individual returns. C corporations generally pay federal income tax at the corporate level.

State income or franchise taxes

Your business may also have state income, franchise, or other business-level tax obligations.

Requirements can become more complicated when a business operates, employs workers, owns property, or makes sales in more than one state.

Self-employment tax

Self-employed individuals may owe self-employment tax in addition to income tax.

The federal self-employment tax rate is generally 15.3%, consisting of Social Security and Medicare taxes, although Social Security wage-base limits and other rules affect the actual calculation.

Self-employment tax is calculated using Schedule SE.

Payroll and employment taxes

Hiring employees creates additional tax responsibilities.

Depending on the circumstances, employers may need to:

Withhold federal income tax
Withhold and pay Social Security and Medicare taxes
Pay federal unemployment tax
Meet state withholding and unemployment requirements
File payroll tax returns and information forms
Provide employees with required year-end tax documents

Payroll is an area where small mistakes can quickly become expensive, so accurate bookkeeping and payroll processes are especially important.

Sales and use tax

Businesses selling taxable products or services may need to collect sales tax from customers and remit it to the appropriate taxing authority.

Use tax can also apply when taxable products or services are purchased without the required sales tax being collected.

Because taxable products, services, rates, and filing requirements vary by jurisdiction, don’t assume that being primarily a service business automatically means sales tax doesn’t apply.

Estimated taxes

The U.S. tax system generally operates on a pay-as-you-go basis.

Business owners who don’t have enough tax withheld during the year may need to make estimated tax payments toward income tax, self-employment tax, and certain other taxes.

Understanding all of these obligations helps you do more than stay compliant. It can also make cash-flow planning much easier.

How Does Business Structure Affect Taxes?

Your legal and tax structure can determine:

Which tax returns you file
How business profits are taxed
Whether self-employment or payroll taxes apply
How owners are compensated
What administrative requirements the business has

That makes entity selection one of the most important tax conversations to have when starting or growing a business.

Sole proprietorship

A sole proprietorship generally reports business income and expenses on Schedule C of the owner’s individual Form 1040.

The business’s net profit generally becomes part of the owner’s taxable income and may also be subject to self-employment tax.

The structure is relatively simple from a tax-administration standpoint, but a sole proprietorship doesn’t provide the same legal separation between owner and business that certain separate legal entities do.

Partnership

A partnership generally files Form 1065, an informational return.

The partnership provides each partner with a Schedule K-1 showing that partner’s share of income, deductions, credits, and other tax items. Partners then report the applicable amounts on their own returns.

An important planning point: partners can owe tax on allocated partnership income even when the partnership hasn’t distributed an equivalent amount of cash.

Limited liability company (LLC)

An LLC is a legal structure created under state law, not a single federal tax classification.

For federal income tax purposes, a domestic single-member LLC is generally disregarded as separate from its owner unless it elects corporate treatment. A domestic LLC with two or more members is generally treated as a partnership unless it elects to be taxed as a corporation.

An eligible LLC may also elect S corporation taxation.

This flexibility is useful, but it also means that simply saying “I’m an LLC” doesn’t tell you how the business is taxed.

S corporation

An S corporation generally passes through income, losses, deductions, and credits to shareholders rather than paying federal income tax, as a traditional C corporation does.

But an S corporation isn’t simply a way to eliminate payroll taxes.

A shareholder who performs more than minor services for an S corporation and receives or is entitled to compensation generally must be treated as an employee. The IRS requires reasonable compensation to be treated as wages before non-wage distributions are used as a substitute for compensation.

S corporation taxation can be valuable in the right circumstances, but payroll, reasonable compensation, eligibility requirements, and additional administrative costs should all be considered.

C corporation

A C corporation is generally a separate federal taxpayer.

The corporation pays tax on its taxable income, and shareholders can also owe tax when corporate earnings are distributed as dividends. This creates the possibility of what’s commonly called double taxation.

C corporations can make sense in certain situations, particularly when ownership, investment, benefit, or growth considerations make the structure attractive. Tax treatment should be evaluated alongside legal and business goals.

Don’t choose an entity based only on taxes

The lowest apparent tax bill isn’t automatically the best business structure.

Liability protection, ownership, financing plans, administrative costs, payroll requirements, future growth, and succession or sale plans can matter just as much.

Before changing your entity or tax election, model the consequences with a qualified tax and legal professional.

Understanding Small Business Tax Deductions

One of the most important concepts for business owners is the ability to deduct qualifying business expenses.

In general, a business expense must be ordinary and necessary for the trade or business to qualify under the applicable tax rules.

Good bookkeeping turns potential deductions into supportable ones.

Home office expenses

Qualifying self-employed taxpayers may be able to deduct expenses associated with business use of their home.

Generally, the space must meet specific business-use requirements, including regular and, in many circumstances, exclusive business use.

Two calculation approaches may be available:

The regular method, based on qualifying actual expenses
The simplified method, currently calculated at $5 per square foot of qualifying business space, up to 300 square feet

Learn more about the home office deduction.

Business mileage and vehicle expenses

If you use a vehicle for business, qualifying business use may be deductible.

Depending on your circumstances and applicable rules, you may use actual vehicle expenses or the IRS standard mileage method.

For 2026, the IRS business standard mileage rate is 72.5 cents per mile.

Regardless of the method used, keep contemporaneous records showing business mileage and business purpose.

Learn more about business mileage deductions.

Equipment and supplies

Computers, machinery, furniture, tools, and other equipment purchased for business may be deductible or depreciable.

Depending on the property and current tax law, options can include:

Regular depreciation
Section 179 expensing
Applicable special depreciation rules

These provisions have detailed eligibility rules and limits, so significant equipment purchases are a good subject for before-the-purchase tax planning.

Business meals

Qualifying business meals may be deductible subject to applicable limitations.

However, entertainment expenses are generally treated differently from qualifying business meals. Don’t assume an expense is deductible merely because a client or prospect was present.

Document the:

Date
Amount
Business purpose
People involved
Business relationship

Professional services

Ordinary and necessary fees paid for business accounting, bookkeeping, legal, consulting, and similar professional services may generally be deductible.

Professional support can also improve the quality of the financial information you use to run the company.

Business insurance

Qualifying insurance premiums associated with operating a business may generally be deductible, depending on the type of coverage and circumstances.

Examples can include liability, property, and certain other business policies.

Advertising and marketing

Ordinary and necessary advertising and promotional expenses are generally deductible business expenses.

That can include expenses such as:

Digital advertising
Website costs
Printed marketing materials
Sponsorships that qualify as advertising
Other promotional activities

Employee compensation and benefits

Qualifying wages, employer payroll costs, and certain employee benefits can generally be business expenses.

Additional tax rules apply to retirement plans, health benefits, owners, related parties, and certain highly compensated employees.

Estimated Taxes for Small Business Owners

One of the most common surprises for new business owners is discovering that taxes often need to be paid during the year, rather than waiting until the annual tax return is filed.

For individuals, estimated tax payments may be required if both of the following generally apply:

You expect to owe at least $1,000 in tax for the year after subtracting withholding and refundable credits; and
Your withholding and refundable credits are expected to be less than the smaller of:
- 90% of the tax shown on your current-year return, or
- 100% of the tax shown on your prior-year return.

Additional rules and exceptions apply, including different rules in certain higher-income situations.

Estimated payments can cover:

Federal income tax
Self-employment tax
Other applicable taxes

State estimated tax obligations may apply separately.

Why estimated taxes cause cash-flow problems

When you receive a paycheck as an employee, taxes are typically withheld automatically.

Business revenue doesn’t work that way.

If you spend all the cash coming into the business without reserving money for taxes, a quarterly payment or tax return can create an unexpected cash shortage.

A better system is to:

Maintain accurate books throughout the year
Review profitability regularly
Estimate tax obligations periodically
Set aside cash for taxes
Revisit estimates when income changes significantly

Tax planning becomes especially valuable when your business is growing quickly or income fluctuates throughout the year.

Business Tax Recordkeeping

Tax deductions are only one reason good bookkeeping matters.

Accurate financial records help you:

Prepare reliable tax returns
Support deductions
Respond to an audit or tax notice
Monitor profitability
Manage cash flow
Build budgets and forecasts
Apply for financing
Make better business decisions

Records may include:

Sales and income records
Receipts
Vendor bills
Invoices
Bank statements
Credit-card statements
Payroll records
Mileage records
Asset purchase documentation
Loan documents
Tax returns and supporting schedules

Just as important, maintain separate business and personal accounts whenever appropriate.

Mixing personal and business transactions makes bookkeeping harder, increases the chance of misclassification, and creates unnecessary work at tax time.

Read our small business bookkeeping basics guide.

Tax Planning vs. Tax Preparation

Tax preparation and tax planning aren’t the same thing.

Tax preparation looks backward

Tax preparation primarily focuses on accurately reporting financial activity that has already occurred.

Once December 31 has passed, many decisions affecting that tax year have already been made.

Tax planning looks forward

Tax planning asks what can still be done before a transaction or deadline.

For example:

Should equipment be purchased this year or next?
How will a large new contract affect estimated payments?
Does the current entity structure still make sense?
Should a retirement plan be established or funded?
What are the tax consequences of hiring an employee?
What happens if the business expands into another state?
How should owner compensation be structured?

The goal isn’t simply to “pay less tax.”

Good tax planning helps you understand the consequences of your choices so you can make decisions that support the business as a whole.

Year-End Tax Planning for Small Businesses

Year-end is an important planning checkpoint, but you don’t have to wait until December.

A useful year-end review may include:

Review your year-to-date financials

Look at:

Revenue
Expenses
Net income
Balance sheet accounts
Cash flow
Payroll
Estimated tax payments

Before making tax decisions, make sure the underlying bookkeeping is accurate.

Forecast full-year profit

A current profit-and-loss statement tells you where you’ve been.

A year-end forecast helps estimate where you’re going.

That difference matters when you’re evaluating estimated taxes and year-end planning opportunities.

Review major purchases

If you’re planning to buy equipment or other significant assets, discuss the timing and tax treatment before committing solely for tax reasons.

Spending $1 merely to obtain a deduction rarely makes sense unless the purchase itself benefits the business.

Review retirement plan opportunities

Depending on your business and circumstances, retirement options may include:

SEP IRA
SIMPLE IRA
Solo 401(k)
Other qualified retirement plans

Contribution limits, establishment deadlines, employee requirements, and deduction rules differ by plan.

Review payroll and owner compensation

This can be especially important for S corporation shareholder-employees.

Make sure payroll reporting and owner compensation have been handled correctly before year-end issues become filing-season problems.

Review estimated payments

Compare payments already made with your updated expected tax liability.

If business results changed significantly during the year, earlier estimates may no longer reflect reality.

Review potential credits and deductions

Ask your tax professional whether business changes during the year created eligibility for tax credits or deductions you haven’t considered.

The key is timing: some planning opportunities disappear once the tax year closes.

Common Small Business Tax Mistakes

Tax problems often begin with everyday bookkeeping and business-process mistakes.

1. Mixing personal and business expenses

Commingling transactions creates unnecessary bookkeeping problems and makes legitimate business expenses harder to identify and support.

2. Ignoring estimated taxes

Waiting until filing season to think about taxes can create a major cash-flow problem and potentially result in underpayment penalties.

3. Failing to keep documentation

A transaction appearing on a bank statement doesn’t always establish why it was a business expense.

Keep receipts and records of business purpose where appropriate.

4. Assuming every business expense is deductible

A purchase doesn’t automatically become deductible because it was paid from a business account.

Personal expenses, capital expenditures, meals, vehicles, travel, gifts, entertainment, and other categories can have special rules.

5. Missing tax deadlines

Late returns, late payments, payroll problems, and missed information-return deadlines can create penalties and interest.

Build tax deadlines into your business calendar.

6. Misclassifying workers

Calling someone an independent contractor doesn’t necessarily make that person one.

Worker classification depends on applicable facts and legal standards. Misclassification can lead to employment-tax and other consequences.

7. Waiting until tax season to clean up the books

Bookkeeping problems are easier to fix monthly than twelve months later.

Regular reconciliations and financial reviews can prevent small errors from turning into expensive cleanup projects.

8. Making decisions solely for a tax deduction

Tax consequences matter, but taxes should support the business strategy—not replace it.

A deduction doesn’t make an unnecessary expense profitable.

Wisconsin Tax Considerations for Small Businesses

Wisconsin business owners need to consider both federal and Wisconsin tax requirements.

The exact obligations depend on your entity, activities, employees, products and services, and where you do business.

Wisconsin income and franchise tax

Corporations doing business in Wisconsin may be subject to Wisconsin corporate franchise or income tax.

Wisconsin’s corporate franchise/income tax rate is currently 7.9%, although the tax treatment of a particular business depends on its structure and circumstances.

Tax-option (S) corporations have separate Wisconsin rules, and income generally flows through to shareholders subject to applicable Wisconsin requirements.

Wisconsin sales and use tax

Businesses making taxable sales in Wisconsin may need to:

Register for the appropriate tax permits
Collect Wisconsin sales tax
Apply applicable county or other local taxes
File sales and use tax returns
Remit tax collected

Wisconsin also has special local taxes that can apply in certain jurisdictions or circumstances, including premier resort area and local exposition taxes.

Don’t determine taxability based simply on whether your business sells “products” or “services.” Wisconsin’s rules determine which particular transactions are taxable.

Wisconsin withholding and employment obligations

Businesses with employees may have Wisconsin withholding, unemployment, reporting, and registration requirements in addition to federal payroll responsibilities.

Wisconsin business registration

Depending on your entity and activities, you may also have registration, licensing, or permit obligations outside the income-tax system.

Review requirements with the Wisconsin Department of Revenue, Wisconsin Department of Financial Institutions, and other relevant agencies.

For a deeper state-specific discussion, see our Wisconsin small business tax guide.

When Should a Small Business Work With a Tax Professional?

Not every bookkeeping question requires a CPA or tax professional.

But professional guidance becomes especially valuable when a decision can create significant or difficult-to-reverse tax consequences.

Consider getting professional advice when you’re:

Starting a business
Choosing or changing an entity structure
Considering an S corporation election
Hiring your first employees
Setting owner compensation
Making a major equipment or real-estate purchase
Expanding into another state
Experiencing rapid revenue or profit growth
Establishing a retirement plan
Buying or selling a business
Bringing in a new owner
Facing an IRS or state tax notice
Preparing for a business sale or succession
Unsure whether a transaction is deductible
Behind on bookkeeping or tax filings

The earlier you involve your tax professional, the more options you may have.

A tax preparer can accurately report a transaction after it happens. A tax advisor who is involved from the outset may be able to help you evaluate how the transaction should be structured.

Small Business Tax FAQs

What taxes does a small business have to pay?

It depends on the business’s structure and activities.

Potential obligations include federal and state income tax, self-employment tax, payroll and employment taxes, sales and use tax, excise taxes, and other state or local taxes.

Your entity structure determines how many of these taxes are calculated and reported.

What taxes does a sole proprietor pay?

A sole proprietor generally reports business income and expenses on Schedule C with Form 1040.

Net earnings from self-employment may be subject to self-employment tax, and business profit can also affect federal and state income tax.

Sales, payroll, excise, or other taxes may apply depending on the business.

Do small business owners have to pay quarterly estimated taxes?

Many do, but not every business owner is automatically required to make quarterly payments.

For 2026, individuals generally look at both the expected $1,000 balance-due threshold and IRS safe-harbor rules involving current- and prior-year tax when determining whether estimated payments are required.

Your circumstances may affect the calculation, so use the current Form 1040-ES instructions or consult a tax professional.

How much is self-employment tax?

The federal self-employment tax rate is generally 15.3%, consisting of 12.4% Social Security tax and 2.9% Medicare tax.

The actual amount isn’t simply 15.3% of all business revenue. Schedule SE rules, the Social Security wage base, other wages, and potentially the Additional Medicare Tax can affect the calculation.

What is the 2026 business mileage rate?

The IRS optional standard mileage rate for qualifying business use of a vehicle is 72.5 cents per mile for 2026.

Eligibility and recordkeeping rules still apply.

Can I deduct a home office?

Qualifying self-employed taxpayers and certain partners may be able to deduct business use of a home when IRS requirements are met.

For many taxpayers, the space generally must be used regularly and exclusively for business, although specific exceptions exist.

A simplified calculation of $5 per square foot, up to 300 square feet, may be available.

Is an LLC taxed differently from a sole proprietorship?

Not necessarily.

“LLC” refers to a state-law entity, not to a specific federal income-tax treatment.

A single-member LLC is generally disregarded for federal income-tax purposes unless another classification is elected. A multi-member LLC is generally taxed as a partnership unless it elects corporate taxation.

An eligible LLC can also elect S corporation treatment.

Does an S corporation eliminate self-employment taxes?

That’s an oversimplification.

An S corporation shareholder who performs services for the corporation may be an employee and must generally receive reasonable compensation subject to applicable employment taxes before non-wage distributions are used.

Whether S corporation taxation creates a meaningful overall benefit depends on profit, compensation, administrative costs, state taxes, and the owner’s circumstances.

What’s the difference between a tax deduction and a tax credit?

A deduction generally reduces the income subject to tax.

A credit generally reduces tax itself, subject to the rules and limitations of the particular credit.

That doesn’t mean every credit is automatically more valuable than every deduction—the value depends on the amount, eligibility requirements, refundability, limitations, and your tax situation.

How long should I keep business tax records?

There isn’t one retention period that applies to every business document.

The appropriate period depends on what the record supports and the applicable limitation period. Certain employment-tax, asset, property, basis, and other records may need to be retained for varying periods.

Your tax professional can help you create a record-retention policy appropriate for your business.

When should I hire a tax professional?

Consider professional support whenever the financial or compliance consequences of getting something wrong become significant.

Entity changes, S corporation elections, employees, multi-state activity, large purchases, ownership changes, tax notices, real estate, and business sales are particularly good times to get advice before acting.

Better Books Make Tax Planning Easier

Good tax planning starts long before a return is prepared.

When your books are accurate and up to date, you and your tax professional can see what’s actually happening in the business. That makes it easier to forecast profit, plan estimated payments, identify questions early, evaluate opportunities, and make decisions with better information.

That’s the difference between reacting to taxes after the year is over and planning for them while you still have choices.

IntegriBooks helps small business owners build the reliable financial foundation needed for better bookkeeping, tax preparation, and year-round planning.

Ready to spend less time worrying about your books and taxes?

Talk with IntegriBooks about your bookkeeping and tax needs.