Business Tax Preparation Checklist 2026: Complete Guide by Entity Type

Key Takeaways

• All businesses need: income documentation (1099s, sales records), expense receipts, bank/credit card statements, prior year tax return, and EIN confirmation letter.
• S-Corps additionally need: W-2s for officer compensation, reasonable compensation documentation, shareholder basis worksheets, and health insurance records for 2%+ shareholders.
• Partnerships need: operating agreement, capital account statements, partner basis worksheets, and documentation for any special allocations.
• Key deadlines: Partnerships and S-Corps file by March 17, 2026. C-Corps and sole proprietors file by April 15, 2026.
• Pro tip: Gather documents 60 days before your deadline. This gives you time to request missing 1099s and resolve questions.

Tax season doesn’t have to mean scrambling through shoe boxes of receipts in March. The difference between a stressful tax season and a smooth one comes down to preparation.

This checklist covers every document you need to gather for your business tax return, organized by entity type. Whether you’re filing Schedule C, Form 1065, Form 1120-S, or Form 1120, you’ll know exactly what to collect and when.

Want a printable version? Download our free PDF checklist at the end of this guide to check off items as you gather them.

Universal Documents (All Business Types)

Before diving into entity-specific requirements, let’s cover the documents every business needs. Regardless of whether you’re an S-Corp, partnership, LLC, or sole proprietor, you’ll need these.

Income Documentation

Gather all records of money coming into your business:

• Total gross revenue for the year (from your accounting software, bank deposits, or invoices)
• 1099-NEC forms received from clients who paid you $600 or more as a contractor
• 1099-K forms from payment processors (Stripe, PayPal, Square, Shopify) if you exceeded their reporting thresholds
• 1099-MISC forms for other income like royalties, rents, or prizes
• Sales records and invoices that support your revenue totals
• Any other income documentation (interest, dividends from business accounts)

Pro tip: Your 1099s should arrive by January 31. If a client paid you $600+ and you haven’t received a 1099 by early February, follow up with them. You still need to report the income even if you don’t receive the form.

Expense Documentation

Collect proof of every business expense you plan to deduct:

• Bank statements from all business accounts (12 months)
• Credit card statements from business credit cards (12 months)
• Receipts for expenses over $75 (the IRS technically requires receipts for $75+, but we recommend keeping all receipts)
• Vendor invoices and bills you paid
• Cancelled checks or payment confirmations for larger expenses

Common expense categories to organize:

• Rent and utilities
• Supplies and materials
• Professional services (legal, accounting, consulting)
• Insurance premiums
• Advertising and marketing
• Software and subscriptions
• Travel and transportation
• Meals (keep detailed records as these are 50% deductible)

For more on what you can deduct, see our small business tax deductions guide.

Asset and Depreciation Records

Track purchases of equipment, vehicles, and property:

• List of equipment purchased during the year (computers, furniture, machinery)
• Vehicle purchase documents if you bought a vehicle for business use
• Property improvements or renovations to business property
• Prior year depreciation schedules (essential for continuing depreciation on existing assets)
• Documentation for any assets sold or disposed of

If you made significant equipment purchases, you may be able to deduct the full cost in the year of purchase using Section 179 or bonus depreciation.

Payroll Documents (If You Have Employees)

For businesses with W-2 employees:

• W-2s issued to all employees
• Form 941 quarterly payroll tax returns (or Form 944 if you’re an annual filer)
• State unemployment (SUTA) filings
• Workers’ compensation insurance records
• Payroll reports showing wages, withholdings, and employer contributions
• Documentation for any employee benefits provided

Other Essential Documents

Don’t forget these foundational documents:

• Prior year tax return (your preparer needs this for reference and carryforward items)
• EIN confirmation letter (form SS-4 or the online confirmation)
• Business formation documents (Articles of Incorporation, Operating Agreement)
• Any IRS correspondence received during the year
• State tax notices or correspondence
• Estimated tax payment records (Form 1040-ES vouchers or confirmation numbers)

S-Corporation Checklist (Form 1120-S)

Filing Deadline: March 17, 2026 (or September 15, 2026 with extension)

S-Corporations have specific documentation requirements beyond the universal list. If you elected S-Corp status for your LLC or incorporated as an S-Corp, you’ll need these additional items.

S-Corp Specific Documents

Shareholder and officer information:

• Shareholder names, SSNs, and ownership percentages (the K-1s depend on this being accurate)
• Officer compensation records including W-2s for all shareholder-employees
• Documentation supporting your reasonable salary determination (comparable salary data, job responsibilities)
• Health insurance premiums paid for 2%+ shareholders (this must be added to their W-2)

Financial records:

• Shareholder loan documentation (promissory notes, interest calculations)
• Distribution records showing dates and amounts paid to each shareholder
• Stock basis tracking worksheets for each shareholder
• Board meeting minutes (if you maintain formal corporate records)
• Shareholder agreement and any amendments

S-Corp Preparation Considerations

Before filing, verify these items:

• Reasonable salary was paid to all officer-shareholders who perform services. The IRS scrutinizes S-Corps where owners take minimal salaries and large distributions. For guidance, see our reasonable compensation guide.
• Health insurance was added to W-2s for shareholders owning 2% or more. This is frequently missed and creates problems.
• Shareholder basis is sufficient for any losses or distributions. You can’t deduct losses or receive tax-free distributions beyond your basis.
• QBI deduction eligibility is documented. The Section 199A deduction can reduce your effective tax rate by up to 20% on pass-through income.

For comprehensive S-Corp guidance, see our S-Corporation tax guide.

Partnership and Multi-Member LLC Checklist (Form 1065)

Filing Deadline: March 17, 2026 (or September 15, 2026 with extension)

Partnerships and multi-member LLCs (taxed as partnerships) require careful documentation of each partner’s activity. K-1 accuracy depends on having complete records.

Partnership Specific Documents

Partner information:

• Partner names, SSNs/EINs, and ownership percentages (exactly as they should appear on K-1s)
• Partnership agreement or LLC operating agreement (allocations must match this document)
• Capital account statements for each partner
• Partner contribution records (cash and property contributed during the year)
• Partner distribution records (dates and amounts distributed to each partner)

Financial records:

• Guaranteed payment documentation (amounts paid to partners for services or capital use)
• Partner basis tracking worksheets for each partner
• Section 754 election documentation if applicable (step-up elections require specific records)
• Special allocation documentation with substantial economic effect analysis (if allocations differ from ownership percentages)
• Records of any partner loans to or from the partnership

Partnership Preparation Considerations

Before filing, confirm:

• Allocations match the operating agreement. The IRS will compare your K-1s to your partnership agreement. Discrepancies create problems.
• Partner basis is tracked accurately. Each partner needs to know their basis to determine if losses are deductible and distributions are taxable.
• Guaranteed payments are properly documented. These are deductible to the partnership and taxable to the receiving partner.
• Capital accounts reconcile. Beginning balance + contributions + allocated income – distributions = ending balance.

For detailed partnership guidance, see our complete guide to partnership taxation.

Single-Member LLC and Sole Proprietor Checklist (Schedule C)

Filing Deadline: April 15, 2026 (or October 15, 2026 with extension)

Single-member LLCs (not electing S-Corp status) and sole proprietors file Schedule C with their personal Form 1040. The documentation is straightforward but thorough.

Schedule C Documents

Income and expense basics:

• All income records (invoices, 1099s, sales reports)
• All expense receipts organized by category
• Year-end accounting software reports (if applicable)

Vehicle and home office:

• Mileage log with dates, destinations, business purpose, and miles driven. The IRS mileage rate for 2025 is $0.70 per mile.
• Home office measurements (square footage of your office and total home square footage)
• Home expenses for home office deduction: mortgage interest or rent, utilities, insurance, repairs

Healthcare and retirement:

• Health insurance premiums paid (the self-employed health insurance deduction is valuable)
• Retirement contributions to SEP-IRA, Solo 401(k), or SIMPLE IRA

Common Schedule C Deductions to Document

Make sure you have receipts or records for:

• Advertising and marketing expenses
• Business insurance premiums
• Professional services (legal, accounting, consulting fees)
• Office supplies and materials
• Software subscriptions and online tools
• Travel expenses (flights, hotels, ground transportation)
• Business meals (50% deductible, requires documentation of business purpose)
• Continuing education and professional development
• Bank fees and merchant processing fees
• Licenses and permits

C-Corporation Checklist (Form 1120)

Filing Deadline: April 15, 2026 (or October 15, 2026 with extension)

C-Corporations have their own set of requirements. While less common for small businesses, if you’re filing Form 1120, here’s what you need.

C-Corp Specific Documents

• Shareholder information and stock records
• Officer compensation records (salaries paid to corporate officers)
• Dividend distribution records (dates, amounts, recipients)
• Corporate meeting minutes and resolutions
• Stock transaction records (issuances, transfers, redemptions)
• Accumulated earnings documentation (if retained earnings are significant)
• Tax credit documentation (R&D credits, work opportunity credits, etc.)
• Prior year NOL carryforward documentation

For C-Corp specific guidance, see our C-Corporation tax guide.

Multi-State Filers: Additional Requirements

If your business operates in multiple states, you’ll need additional documentation for each state where you have filing obligations.

Gather for each state:

• Revenue breakdown by state (sales by customer location or delivery destination)
• Payroll breakdown by state (wages paid to employees in each state)
• Property and assets by state (office locations, inventory, equipment)
• Prior year state tax returns
• State-specific forms and schedules
• Nexus analysis documentation (what triggered your filing requirement in each state)

Multi-state filing is complex. Economic nexus rules vary by state, and getting apportionment wrong can mean overpaying in some states and underpaying in others. See our multi-state partnership filing guide for more details.

Documents to Request from Third Parties

Some documents come from others. Here’s when to expect them and who to follow up with if they’re missing.

Important: If you invest in partnerships or S-Corps that issue K-1s, those K-1s aren’t due until March 15. This is why many business owners who receive K-1s file extensions for their personal returns.

Organizing Your Documents

A little organization goes a long way. Here’s a folder structure that works well:

Recommended digital folder structure:

2025 Tax Documents/

• Income/
  • 1099s Received/
  • Sales Records/
  • Other Income/
• Expenses/
  • Bank Statements/
  • Credit Card Statements/
  • Receipts by Category/
• Payroll/
  • W-2s Issued/
  • Quarterly Returns/
• Assets/
  • Equipment Purchases/
  • Depreciation Schedules/
• Entity Documents/
  • Formation Docs/
  • Prior Year Returns/

Digital storage tips:

• Use cloud storage (Google Drive, Dropbox, OneDrive) so files are backed up and accessible
• Name files consistently: “2025-01-15_Vendor-Name_Invoice_$500.pdf” makes searching easy
• Scan paper receipts immediately. Thermal receipts fade, and you don’t want to lose deductions because the receipt became unreadable
• Keep everything for 7 years. The IRS can audit up to 6 years back in certain situations

If keeping up with this throughout the year sounds overwhelming, our bookkeeping services can help you stay organized automatically.

Tax Preparation Timeline for 2026

Here’s when to do what:

For detailed deadline information, see our business tax extension deadlines guide.

Download Your Free Checklist

Want all of this in a printable format you can check off as you go?

Our free PDF checklist includes:

• Complete document checklists for every entity type
• Document organization tips
• Key 2026 deadlines
• Space to track what you’ve gathered and what’s missing

Download the checklist and you’ll be ready for tax season instead of scrambling.

Need Help Getting Organized?

If gathering all these documents feels overwhelming, you’re not alone. Many business owners find that the stress of tax season comes from disorganized records throughout the year.

Two ways we can help:

1. Year-round bookkeeping that keeps your records organized automatically, so tax season is just a matter of generating reports. See our bookkeeping services.
2. Professional tax preparation where we handle the complexity, identify optimization opportunities, and ensure accuracy. See our tax preparation services.

Whether you file yourself or work with a professional, having organized records makes everything easier. If you’d like to discuss your situation or get help preparing for tax season, schedule a consultation and we’ll make sure nothing gets missed.