How do you file business taxes?

Business tax deadlines and forms depend on your entity: partnerships and S-corps file by March 15 (Form 1065 or 1120-S), sole proprietors and C-corps file by April 15 (Schedule C or Form 1120). Gather bank statements, P&L, balance sheet, payroll records, and asset purchases before filing. Key deductions include Section 179, home office, vehicle, and professional services.

Filing deadlines by entity type

Sole proprietorship (Schedule C, attached to Form 1040) — April 15.
Partnership (Form 1065) — March 15 for calendar-year partnerships.
S-Corporation (Form 1120-S) — March 15 for calendar-year S-corps.
C-Corporation (Form 1120) — April 15 for calendar-year C-corps.
Fiscal-year businesses — generally 75 days after fiscal year-end (partnerships/S-corps) or 105 days after year-end (C-corps).
Extensions: 6-month extension available (Form 7004 for business returns, Form 4868 for individual). Extension to file ≠ extension to pay — estimated taxes still due on original deadline.

Required forms by entity

The IRS Small Business & Self-Employed Tax Center at irs.gov/businesses/small-businesses-self-employed has the full form library for each entity type. Key forms:

Schedule C (Form 1040) — sole proprietors report business income and expenses on this schedule, attached to personal return.
Form 1065 — partnership information return; each partner receives Schedule K-1 showing their share of income.
Form 1120-S — S-corporation information return; shareholders receive Schedule K-1.
Form 1120 — C-corporation tax return; the corporation itself pays corporate income tax.
Form 941 — quarterly payroll tax return if you have employees (filed separately from income taxes).
Form 1099-NEC — report payments to independent contractors of $600+ (due January 31).

Documents to gather before filing

12 months of business bank statements — reconcile to gross receipts on the return.
Profit & loss statement (P&L) — income, COGS, and operating expenses organized by category.
Balance sheet — assets, liabilities, and equity as of year-end.
Mileage log — required to deduct vehicle use; the IRS standard mileage rate changes annually.
Asset purchase records — equipment, vehicles, furniture bought during the year for Section 179 or MACRS depreciation.
Payroll records — W-2s issued, quarterly 941s filed, payroll tax deposits.
Receipts for deductible expenses — meals (50% deductible), travel, professional services, advertising.

Key deductions for small businesses

Section 179 — immediate first-year expensing of qualifying equipment and business property. The 2024 Section 179 deduction limit is $1,220,000 per IRS Publication 946.
Home office deduction — requires exclusive-and-regular business use of a defined home space; either simplified method ($5/sq ft up to 300 sq ft) or actual expense method.
Vehicle deduction — business mileage at the IRS standard rate, or actual vehicle expenses allocated to business use percentage.
Professional services — attorney, accountant, and consultant fees paid for business purposes are fully deductible.
Business interest expense — interest paid on business loans is deductible (subject to Section 163(j) limitations for larger businesses).
Qualified Business Income (QBI) deduction — pass-through entities may deduct up to 20% of qualified business income under Section 199A.

When to use a CPA

Use a CPA if: you have employees, own business real estate, have multiple owners, made significant equipment purchases, received a large contract, had revenue above $500K, or received an IRS notice. Tax complexity rises sharply with employee count and entity type — the cost of a CPA is itself a deductible professional expense.

Apply at ClearValue Lending

Lenders require 2 years of business tax returns for most SBA and term loans. ClearValue Lending connects small businesses to lenders who work with sole proprietors, LLCs, S-corps, and C-corps across the full range of financing products. Apply through the ClearValue Lending portal when your tax returns are filed and current.

Sources

The IRS Small Business & Self-Employed Tax Center at irs.gov/businesses/small-businesses-self-employed is the official hub for business tax filing resources, including forms, schedules, due dates, and estimated tax guidance for all entity types. — IRS — Small Business & Self-Employed Tax Center
IRS Publication 334 (Tax Guide for Small Business) covers Schedule C preparation, business deductions, home office rules, vehicle deductions, and self-employment tax for sole proprietors and single-member LLCs. — IRS Publication 334
IRS Publication 946 (How to Depreciate Property) covers Section 179 expensing, MACRS depreciation schedules, and bonus depreciation rules applicable to business equipment purchases. The 2024 Section 179 deduction limit is $1,220,000. — IRS Publication 946
The Federal Reserve Small Business Credit Survey 2024 found that lenders request 2 years of business tax returns as a standard documentation requirement for SBA and term loan applications across all entity types. — Fed SBC Survey 2024

Key takeaways

Partnerships and S-corps are due March 15; sole proprietors and C-corps are due April 15. Fiscal-year businesses have different deadlines.
Gather 12 months of bank statements, a full P&L, balance sheet, mileage log, and asset purchase records before starting.
Section 179 allows immediate first-year expensing of equipment purchases up to $1,220,000 (2024 limit per IRS Pub 946).
Pass-through entities may qualify for the Section 199A QBI deduction — up to 20% of qualified business income.
Lenders require 2 years of filed business tax returns for SBA and most bank term loans — keep them current.