Background

Starting and filing your first business return is often the first formal interaction a new owner has with federal tax rules. In my 15 years advising small-business owners, I’ve seen well-organized first filings prevent audits, reduce missed deductions, and make future borrowing and accounting far easier. The IRS provides basic guidance for small businesses and the self-employed (see IRS Small Business & Self-Employed) and detailed instructions in Publication 334 (Tax Guide for Small Business) and Publication 535 (Business Expenses).

How filing works — the essentials

  • Identify your business entity: sole proprietorship, partnership, S or C corporation, or LLC taxed as one of those types. Entity type determines which return you file and when it’s due.
  • Gather records: income (invoices, 1099s, bank deposits), expenses (receipts, statements), payroll records if you have employees, and asset purchases for depreciation.
  • Choose and complete the correct forms and schedules. File electronically when possible to reduce errors and speed processing.

Key forms and typical deadlines

Form / Schedule Use for Typical due date (annual)
Schedule C (Form 1040) Sole proprietors/report business profit or loss With Form 1040 — usually Apr 15
Form 1065 + Schedule K-1 Partnerships — report business activity and partner allocations Mar 15
Form 1120 C corporations — corporate income tax return Apr 15
Form 1120‑S + Schedule K-1 S corporations — passthrough income reporting Mar 15

(Confirm current-year due dates on the IRS site—deadlines shift for weekends/holidays and special relief years.)

Common deductions and tax rules to watch

  • Ordinary and necessary business expenses: supplies, rent, utilities, advertising, and professional fees (see IRS Pub 535).
  • Home office deduction: must meet specific rules and a simplified or actual-expense method can be used.
  • Vehicle expenses: choose between standard mileage or actual expense method and keep a contemporaneous log.
  • Depreciation and Section 179: claim on capital assets instead of deducting the full cost in year one unless eligible.

Real-world example

A solo freelancer I worked with tracked income and expenses by client and used cloud accounting with automated bank feeds. That organization reduced prep time from days to a few hours and uncovered eligible home office and business-supplies deductions she’d missed earlier.

Practical filing strategies (professional tips)

  1. Start year-round bookkeeping: reconcile bank accounts monthly and tag every transaction to categories that map to tax lines. For more on recordkeeping best practices, see our article on Tax Compliance — Essential Recordkeeping Practices to Stay Compliant for Small Businesses.
  2. Use estimated tax planning: if you expect to owe $1,000+ when you file, make quarterly estimated payments to avoid penalties.
  3. Separate personal and business finances: a dedicated business bank account and card simplifies reporting and substantiation.
  4. Consider a tax pro for your first return: a CPA or enrolled agent can ensure entity elections, depreciation choices, and credits are handled correctly.
  5. Keep an audit file: maintain a folder (digital or physical) with key documents for the first 3–7 years in case of IRS inquiries. See our Compliance Checklist for New Small Businesses: First-Year Tax Tasks for an actionable startup checklist.

Common mistakes to avoid

  • Poor recordkeeping that mixes personal and business expenses.
  • Missing required forms (for example, failing to issue or collect 1099-NEC forms where required).
  • Overlooking payroll-related filings and trust-fund liabilities when you have employees.

Where to find authoritative guidance

Professional disclaimer

This article is educational and does not substitute for personalized tax advice. Tax laws and deadlines change; consult a qualified tax professional (CPA, enrolled agent, or tax attorney) for guidance tailored to your situation.

Sources & notes

Information summarized from IRS guidance (Publications 334 and 535) and professional experience helping first‑time filers.