This guide is for individual taxpayers and sole proprietors who want to organize their records and file their returns correctly. It covers the basics, the documents you need, how filing works for individuals and small businesses, and the most common mistakes. A tax professional can also help you organize and prepare your return.
What Have We Learned From Preparing Returns for Individuals and Sole Proprietors?
Every return our team prepares starts with the same document checklist and the same review of income, deductions, and credits. Because we use the same process each time, we see the same patterns year after year. In our experience:
- Missing 1099s are the most common gap. Freelance, interest, and brokerage 1099s often arrive late or get overlooked.
- Sole proprietors under-track expenses. Software, mileage, and home office costs are the deductions most often missed.
- Extensions are misunderstood. Many people think an extension also gives them more time to pay.
We tested what an extension actually changes. For a 2025 individual return, Form 4868 moves the filing deadline from April 15, 2026 to October 15, 2026. That’s 6 extra months to file. But it gives 0 extra days to pay. Any tax owed is still due on April 15, 2026, and interest runs from that date (IRS: About Form 4868).
We also ran the self-employment tax math. Self-employment tax applies to 92.35% of net profit at a rate of 15.3%. Together, that’s about 14.13% of a sole proprietor’s net profit, before any income tax (IRS Topic No. 554).
What we’ve learned is that most filing problems start months before tax season, with missing records, not on filing day.
What Are the Tax Prep Basics?
What Do the Key Income Terms Mean?
- Gross income: your total income before any adjustments.
- Adjusted gross income (AGI): gross income minus eligible adjustments.
- Taxable income: what remains after deductions. Your income tax is calculated on this amount.
When Is the 2025 Tax Return Due?
- 2025 federal individual returns are generally due April 15, 2026.
- Form 4868 gives an automatic extension to file until October 15, 2026.
- An extension to file does not extend the time to pay.
How Do Sole Proprietors Report Business Income?
Sole proprietors generally report business income and expenses on Schedule C, filed with Form 1040.
What Documents Do You Need to Prepare Your Taxes?
- W-2 forms (wage statements)
- 1099 forms (NEC, MISC, INT, DIV, R, and others)
- A copy of last year’s tax return
- Business income and expense records for Schedule C. A profit and loss statement makes this much easier.
- Rental income and expense records, if you have rental property
- Form 1099-B or 1099-DA investment statements (stocks, crypto)
- Mortgage interest statement (Form 1098)
- Medical expense records, if you plan to itemize
- Charitable donation receipts
- Education documents (Form 1098-T, student loan interest)
- Each dependent’s SSN, date of birth, and relationship to you
- Childcare expense records, if you have them
How Does Filing Work for Individuals and Small Businesses?
How Does Filing Work for Individuals?
There are five filing statuses: Single, Married Filing Jointly, Married Filing Separately, Head of Household, and Qualifying Surviving Spouse. Your status affects your tax rates, standard deduction, and which credits you can claim.
W-2 wages are employment income. Business income is your gross receipts minus allowable expenses. Deductions lower your taxable income. Credits lower your tax directly. Interest, dividends, capital gains, and rental income each have their own reporting rules.
How Does Filing Work for Small Businesses?
Business income and expenses: Gross receipts include payments for goods or services. Common expenses include advertising, supplies, software, insurance, and professional fees.
Home office, mileage, and equipment:
- Simplified home office method: $5 per square foot, up to 300 square feet (2025).
- Standard business mileage rate: 70 cents per mile (2025).
- Equipment may be depreciated or deducted under IRS rules.
Self-employment and estimated taxes:
- Self-employment tax generally applies when net self-employment earnings are $400 or more.
- The rate is 15.3%, applied to 92.35% of net profit.
- You may need to make quarterly estimated tax payments.
What Are the Most Common Tax Filing Errors?
- Wrong filing status
- Unreported income from 1099s, freelance work, investments, rentals, or retirement accounts
- Missed deductions or credits
- Poor documentation for business, education, home office, charitable, dependent, and earned income items
Remember the difference between deductions and credits. A deduction lowers the income you’re taxed on. A credit lowers your tax dollar for dollar. Keep personal and business expenses separate, and see our guide on business deductions.
How Did a Review Find an Overlooked Deduction for a Retail Client? (Example From Our Work)
Details are generalized to protect client confidentiality.
Situation: A small local retail business owner, filing as a sole proprietor, had already filed her return. She asked us to look over her records because she felt her tax bill was too high.
What we did:
- Reviewed all 12 months of her business records, line by line, against her Schedule C.
- Matched every bank and card transaction to an expense category.
- Found a deductible business expense that had been left off the original return.
- Confirmed she had the receipts to support it.
- Filed an amended return to claim it.
What changed: The amended return corrected the overpayment, and she received a refund of $1,450. She also moved to monthly bookkeeping, so expenses are categorized as they happen instead of at tax time.
In our experience, a full 12-month review is the most reliable way to catch missed deductions. Most of them hide in everyday transactions, not large purchases.
Frequently Asked Questions
What documents are needed for tax preparation?
Common documents include W-2s, 1099s, last year’s return, business and rental records, investment and mortgage statements, donation receipts, education documents, and dependent information when it applies.
What is Schedule C?
Schedule C is generally used by sole proprietors to report business income and expenses with Form 1040.
What are common tax filing mistakes?
The most common mistakes are the wrong filing status, missed income, overlooked deductions or credits, and poor documentation of business expenses.
Do I need to pay estimated taxes?
You may need to, depending on your income. It is especially likely if you have self-employment income and not enough tax withheld.
Does an extension give me more time to pay?
No. Form 4868 gives you more time to file, until October 15, 2026 for a 2025 return. Any tax you owe is still due by April 15, 2026.
Need help preparing your return? Explore ProfitsView’s tax services or contact our team.
This article is for general information only and is not tax advice. Check current IRS guidance or talk to a tax professional about your situation.
