Starting a business is exciting but if you’re not careful, the way you handle your books early on can cost you time, money, and peace of mind down the road. As a bookkeeper to small business owners, I’ve seen firsthand how common accounting mistakes can create long-term headaches and can blur the true health of the company at its outset. Here are five bookkeeping mistakes made by new entrepreneurs. Keep reading on to see our honorable mention and potentially the most frequent blunder.

1. Mixing Business and Personal Finances

The mistake: Using a personal bank account or credit card to pay for business expenses and vice versa.

Why it matters:

  • Makes tax filing harder

  • Creates confusion around cash flow

  • Increases risk of missing deductions

  • Complicates potential audits

How to fix it:

  • Open a dedicated business checking account and business credit card.

  • Use accounting software (like QuickBooks or Xero) that links to your business accounts.

  • Avoid transferring funds back and forth without proper documentation.

Pro Tip: Pay yourself through a formal owner’s draw or payroll instead of paying business expenses from your personal card.

2. DIY Bookkeeping Without Understanding the Basics

The mistake: Using spreadsheets or free tools without knowing accounting fundamentals.

Why it matters:

  • Leads to inaccurate categorization

  • Misses key tax deductions

  • Can result in incorrect profit/loss reports

How to fix it:

  • Use user-friendly software designed for small business owners.

  • Hire a bookkeeper or accountant to help set up your chart of accounts.

  • Invest in a quick training session or consultation so you understand the basics.

Remember: Your financial reports are only as good as the data you enter.

3. Forgetting to Track Receipts and Documentation

The mistake: Failing to save receipts or keep backup documentation for expenses.

Why it matters:

  • The IRS requires substantiation for deductions

  • You may lose out on legitimate write-offs

  • Poor recordkeeping increases audit risk

How to fix it:

  • Use a digital receipt tracker (like Hubdoc, Expensify, or Dext).

  • Snap photos of receipts as soon as you receive them.

  • Match each receipt to a categorized transaction in your books.

Organized books = easier taxes + peace of mind.

4. Not Reconciling Bank Accounts Regularly

The mistake: Assuming your bank feed data is accurate and never reconciling.

Why it matters:

  • Duplicate or missing transactions may go unnoticed

  • Fraudulent charges may slip through

  • Financial reports will be unreliable

How to fix it:

  • Reconcile your books monthly against your bank and credit card statements.

  • Use software with built-in reconciliation tools.

  • Ask your bookkeeper to flag mismatches or unreconciled items immediately.

What gets measured gets managed. Reconciliation is your first line of defense.

5. Waiting Until Tax Time to Organize Everything

The mistake: Ignoring bookkeeping until your CPA asks for your books in March or April.

Why it matters:

  • Rush leads to errors or missed deductions

  • Increases stress and tax prep fees

  • Prevents real-time decision-making based on accurate financials

How to fix it:

  • Schedule monthly or bi-weekly bookkeeping check-ins

  • Automate as much as possible (invoicing, expense tracking, bank feeds)

  • Work with a professional from the start—even if only for oversight

Bookkeeping is not a once-a-year chore—it’s a monthly business asset.

Honorable Mention: Not Setting Aside Money for Taxes

Many new entrepreneurs are rightly focused on growth and delivering their product or service. But in the midst of building momentum, one critical habit often gets overlooked: planning for taxes. A common mistake is failing to set aside a portion of revenue throughout the year—especially when owners aren’t yet drawing a formal salary and our merely drawing down the bank account for compensation.

To stay ahead, entrepreneurs should consistently allocate 20–25% of all revenue for taxes. With this proactive approach, you’ll be financially prepared when it’s time to pay Uncle Sam. And if you end up owing less than expected? Congratulations, you’ve just built a savings buffer that can be reinvested back into your business growth. Once that box is checked approach your bookkeeper/tax preparer and ask about tax planning.

Final Thoughts

Bookkeeping may not be glamorous, but it’s a critical part of building a sustainable, profitable business. Avoiding these 5 mistakes made by entrepreneurs early on sets the stage for better decision-making, fewer surprises, and long-term growth. It’s essential for new entrepreneurs to develop a strong understanding of how a business operates from financial, tax, and legal perspectives. Mastering these skills empowers them to take control of their operations, navigate market cycles with confidence, and strategically plan for the future. It also shows them that having outsourced professional services in their operation is a huge value add because it allows them to focus on what they do best.

Need help with your setup? Reach out and let’s make sure your foundation is solid.