As a small business owner, you likely already know that the tax landscape can be complex, but if you’re using bookkeeping, tax and accounting services, the rules and regulations may not pose any particular problem for you. For those businesses trying to save a dime by handling their own taxes every year however, they may not yet know that even the smallest of errors or misunderstanding of the rules, could cost them dearly.

With help from tax planning in Coral Gables, you can step into filing season filled with confidence, year on year. For those going it alone, here are some of the biggest tax errors you might inadvertently make in 2026:

Misclassification of your business structure

If you made a snappy decision about whether to form an LLC partnership or S-Corporation, you may not have a full and complete understanding of just how your chosen structure can impact your tax obligations.

With personal liability, estimated payments and long-term planning all impacted by your chosen entity type, selecting the wrong one can have costly consequences.

Misclassification of workers

The IRS continue to hone in on this as we enter 2026, and if you misclassify an employee, you could face steep penalties for failure to withhold payroll taxes, contributions, and reporting requirements.

Missing out on valuable deductions

Legitimate deductions are often overlooked by harried business owners who don’t have the time or expertise to find ways of lowering their tax bill. Over time, this will reduce their profitability as their taxable income increases.

Making bookkeeping errors

DIY bookkeeping mistakes that may seem inconsequential at the time they were made, can easily (and often do) come back to haunt business owners when tax season arrives. Numbers that simply don’t align, always spell trouble.

Poor recordkeeping

As simple as this process is to follow, record retention continues to blight small business owners in 2026. Documentation for expenses, payroll, income and depreciation must be meticulously kept, and usually for several years. Failure to do so means deductions could be disallowed, or taxes unfavorably adjusted.

Failure to make accurate estimated tax payments

For many pass-through entities, accurate quarterly estimated tax payments are mandated by the IRS. When these aren’t made, stiff penalties may be incurred that could so easily have been avoided.

Neglecting payroll tax obligations

Without professional help, calculating payroll taxes can quickly become a problem for small business owners, but without timely deposits, reporting and withholding that’s accurate, serious consequences from the IRS can ensue.

Incorrectly tracking depreciation

Involving calculations that are made on a long-term basis rather than in a single year, depreciation rules often trip small business owners up. However, by failing to track assets such as vehicles and equipment, tax filings and financial statements can become distorted.

Year-end planning that starts too late

Tax strategies should be ongoing throughout the year, and with help from a bookkeeper, accountant and tax specialist, filing at the end of the year, should be a breeze. Choose to go it alone, on the other hand, and you run the risk of filing an incomplete return when the deadline strikes.

Failure to keep personal and business expenses separate

This is one of the most common tax mistakes made by small business owners, with comingling of finances leading to all manner of complications, and not just at tax time. Professional tax preparation in Miami can help you file your taxes, but only you can tell them what has been spent for the business, and what has been spent for you.

Other common tax errors involve neglecting retirement contributions and failing to understand your tax requirements at state level. Fortunately, these and all of the mistakes listed above can be avoided by partnering with tax and accounting experts; if you aren’t already, you really should be.