Tax Compliance Checklist for Startups

Startup tax compliance covers several overlapping obligations: registering your business, getting an Employer Identification Number (EIN), paying estimated taxes, handling payroll if you have employees, reporting contractor payments, and keeping records the IRS can verify. The specific requirements depend on your business structure and whether you have employees.

Before you can file taxes or hire anyone, you need 2 things in place: a registered business entity (if your structure requires it) and an Employer Identification Number (EIN) from the IRS. Most startups need both before they open a bank account or bring on their first employee.

LLCs, limited liability partnerships, and corporations need to register with their state's Secretary of State. Sole proprietorships and general partnerships typically don't. Regardless of structure, you'll need an EIN if you have employees, operate as a corporation or partnership, or want to open a business bank account. Sole proprietors and single-member LLCs without employees can use a Social Security number instead, but an EIN keeps your personal number off business documents.

Apply for an EIN at irs.gov/ein. Online applications are processed immediately. The IRS online application is available Monday through Friday, 7 AM – 10 PM ET.

Your business structure determines which tax forms you file, whether you pay self-employment tax, and whether your business pays tax at the entity level or passes income through to you personally. Getting this right early prevents surprises at filing time.

Sole proprietorship

Business income and losses are reported on your personal return using Schedule C (Form 1040). You pay self-employment tax — 15.3% on net earnings — on top of income tax.

Partnership

Partnerships file Form 1065 and issue Schedule K-1 to each partner. Income passes through to partners' personal returns. Partners pay self-employment tax on their share of earnings.

LLC

By default, a single-member LLC is taxed as a sole proprietorship and a multi-member LLC is taxed as a partnership. You can elect C corporation or S corporation treatment by filing Form 8832 or Form 2553 with the IRS. Each election changes your filing requirements and self-employment tax exposure.

C corporation

C corporations are separate taxable entities. The business pays corporate income tax on profits, and shareholders pay personal income tax again on dividends — the double-taxation trade-off that comes with C Corp status. File Form 1120 annually.

S corporation

S corporations avoid double taxation by passing income through to shareholders' personal returns via Form 1120-S and Schedule K-1. Shareholder-employees must pay themselves a reasonable salary and pay payroll taxes on that salary — self-employment tax applies only to the salary, not to distributions.

If you expect to owe at least $1,000 in federal tax for the year — after withholding and credits — you need to make quarterly estimated tax payments. Corporations have a lower threshold: $500 or more in expected corporate income tax. Missing these payments means underpayment penalties, even if you pay everything owed at filing.

The federal quarterly due dates are April 15, June 15, September 15, and January 15 of the following year — adjusted when those dates fall on weekends or holidays. Sole proprietors and single-member LLC owners use Form 1040-ES. Corporations use Form 1120-W to figure their payments.

Most new business owners underestimate their first-year tax bill because there's no employer withholding to fall back on. Setting aside 25–30% of net income each quarter is a reasonable starting point until you have a clearer picture of your effective rate.

Once you hire employees, payroll tax obligations start immediately. You're responsible for withholding federal income tax, Social Security, and Medicare from each paycheck — and for paying the employer's matching share of Social Security and Medicare on top of that.

• Social Security: withhold 6.2% from employee wages (up to the annual wage base) and pay a matching 6.2% as the employer

• Medicare: withhold 1.45% from all employee wages with no wage base cap, plus a matching 1.45% employer share. An additional 0.9% applies to wages over $200,000 — withhold that from the employee, no employer match

• Federal income tax: withhold based on each employee's W-4 and IRS withholding tables

• FUTA: pay federal unemployment tax using Form 940. Register for a state unemployment insurance account number before your first hire

File Form 941 quarterly to report wages paid and taxes withheld. Send W-2s to employees and file them with the Social Security Administration by January 31 each year. A tax professional can help you figure out your deposit schedule — it varies based on how much payroll tax you owe.

If you pay an independent contractor $600 or more in a calendar year, you need to file Form 1099-NEC with the IRS and send a copy to the contractor. The $600 threshold resets per contractor, per year. Before making any reportable payment, have the contractor fill out a W-9 — it confirms their tax classification and Taxpayer Identification Number (TIN).

Both the contractor copy and the IRS filing are due by January 31 of the year following payment. Missing this deadline can mean penalties per form — and if the IRS determines a contractor should have been classified as an employee, you can owe back payroll taxes, unpaid Social Security and Medicare contributions, plus penalties and interest.

Sales tax is governed by the states, not the federal government, and the rules vary widely. Generally, you collect and remit sales tax based on where your customers are located — not where your business is. If you sell across state lines, you may have nexus obligations in multiple states depending on your sales volume or physical presence there.

The federal government levies excise taxes on fuel, transportation, and certain other goods. Some states add their own excise taxes on a broader range of products. If your business sells or uses any of these items, check whether federal or state excise registration is required before you start selling.

Sales and excise tax rules are among the most state-specific obligations a startup faces. A tax professional familiar with your state can help you figure out your registration and collection requirements before you make your first sale.

New businesses can deduct up to $5,000 in startup costs and $5,000 in organizational expenses in their first year of operation. Amounts above those thresholds are amortized over 15 years. These deductions phase out if your total startup costs exceed $50,000, so tracking every pre-launch expense matters.

• R&D Tax Credit: claim a credit for qualified research wages and supply costs if your business conducts eligible research activities. Startups with under $5 million in gross receipts can apply up to $250,000 of the credit against payroll taxes

• Work Opportunity Tax Credit (WOTC): reduces your tax liability dollar-for-dollar when you hire individuals from targeted groups facing employment barriers

• Home office deduction: deduct a portion of home expenses if you use part of your home exclusively and regularly for business. Use actual expenses or the IRS simplified method

Most founders leave money on the table in year one because they don't track pre-launch expenses or don't know the R&D credit applies to software and product development work, not just lab research. A tax professional can help you figure out which credits your business qualifies for before you file.

The IRS requires businesses to keep records that support every entry on their tax returns. The minimum retention period is 3 years from the date you filed the return. That extends to 6 years if you underreport income by more than 25%, and records must be kept indefinitely if fraud is involved or if you never properly depreciated an asset.

• Gross receipts: sales slips, invoices, deposit slips, and bank statements

• Expenses: paid bills, receipts, canceled checks, and account statements

• Payroll: employee W-4s, payroll registers, tax deposit records, and copies of filed Forms 941 and W-2

• Travel and deductible expenses: mileage logs, receipts, and the business purpose for each expense

• Asset records: purchase price, date placed in service, depreciation taken, and sale price for any business property

A dedicated business bank account is the foundation of any recordkeeping system. When business and personal finances run through the same account, sorting deductible expenses from personal ones takes hours. Keep them separate from day one.