Starting a business is exciting. The first tax bill? Not so much. New business owners are routinely blindsided by self-employment tax, quarterly payment requirements, and a tax system that works completely differently from the W-2 world they're used to.
Here are nine things every first-time business owner needs to know before their first tax season.
1. You Pay Two Taxes Now, Not One
As a W-2 employee, your employer handled half of your Social Security and Medicare taxes. As a business owner, you pay both halves — 15.3% self-employment tax on top of income tax.
On $80,000 in net profit, that's approximately $11,300 in SE tax alone. Budget for a total federal tax rate of 25-35%.
2. Nobody Withholds Taxes for You
There's no HR department deducting taxes from your income. You're responsible for making quarterly estimated tax payments to the IRS (April 15, June 15, September 15, January 15). Miss them and you'll face underpayment penalties.
Rule of thumb: Set aside 25-30% of every dollar you earn in a separate savings account for taxes.
3. Choose Your Entity Structure Wisely
Sole proprietorship, LLC, S-Corp, C-Corp — this decision affects how much you pay in taxes for the life of your business. An LLC doesn't save taxes by itself (it's taxed the same as a sole proprietorship by default). The S-Corp election is what reduces self-employment tax — but only when your income justifies the additional compliance costs.
Don't guess. A CPA consultation ($200-$500) can save you thousands per year by getting the entity right from the start.
4. Track Every Expense from Day One
Every ordinary and necessary business expense is deductible — but only if you can prove it. Set up:
- A dedicated business bank account
- A dedicated business credit card
- Accounting software (QuickBooks, Wave, or FreshBooks)
- A system for saving receipts (apps like Dext or the QuickBooks mobile app)
Start tracking from your very first business expense. Don't wait until tax time to reconstruct a year of spending.
5. You Can Deduct Startup Costs
Expenses incurred before your business officially opens are deductible:
- Market research
- Business planning
- Legal and accounting fees for formation
- Training and education
- Pre-opening advertising
- Travel to set up the business
You can deduct up to $5,000 in startup costs immediately (if total costs are under $50,000). The rest is amortized over 15 years.
6. Your Home Office Is a Deduction
If you work from home in a dedicated space used exclusively for business, you qualify for the home office deduction. The actual expense method (percentage of rent, utilities, insurance, internet) typically produces $2,500-$5,000 per year.
Claim it from your first month in business.
7. Track Your Mileage
Every business drive — to clients, to the bank, to buy supplies — is deductible at 67 cents per mile. Over a year, this adds up to thousands in deductions.
Start a mileage log today. No log = no deduction if audited.
8. Health Insurance Is Deductible
If you're self-employed and not covered by a spouse's employer plan, 100% of your health insurance premiums (medical, dental, vision) are deductible. For a family paying $12,000-$20,000 per year in premiums, this is a major deduction.
9. Get a CPA Early — Not After Your First Mistake
The most expensive time to hire a CPA is after you've already made costly decisions — wrong entity, missed estimated payments, no expense tracking, unclaimed deductions.
The least expensive time is before your first tax year ends. A CPA sets you up correctly from the start: right entity, right accounting system, right estimated payments, and every deduction claimed.
Your First Tax Year Sets the Foundation
The decisions you make in your first year of business — how you structure, what you track, how you pay taxes — set the pattern for every year that follows. Getting it right now saves you money for the life of your business.
Find a CPA who specializes in new business setup and small business tax at ListMyCpa.com. Search by state, city, and specialization to start your business on the right tax foundation.