Five common accounting mistakes in small businesses (and how to avoid them)

Accounting is an essential part of running any business, particularly in micro, small and medium-sized enterprises (SMEs), where resources are often limited. Even so, business owners frequently make management mistakes that undermine the company's financial health.

This article identifies five of the most common accounting mistakes and sets out practical ways to avoid them.

1. Mixing personal and company finances

The mistake: using the same bank account or payment methods for personal and business expenses.

Consequences: this practice makes financial organisation harder, complicates the accounts and can lead to problems, breaches and fines in the event of an audit or tax inspection.

How to avoid it:

• Open a bank account used exclusively for the business.
• Set a fixed salary for the managing partners, based on the household budget and compatible with the business budget.
• Keep personal and professional spending strictly separate.

2. Records that are not kept up to date

The mistake: putting off the recording of accounting transactions and letting the work pile up until statutory returns are due.

Consequences: it can produce errors in financial reports, a loss of control over cash and management decisions that are poorly grounded.

How to avoid it:

• Set up weekly routines for updating records.
• Use invoicing or accounting software suited to the size of the business.
• Automate administrative processes wherever possible.

3. Not keeping invoices and supporting documents

The mistake: throwing away or forgetting to file invoices, receipts and other documents relevant to the accounts.

Consequences: losing documents jeopardises the deduction of expenses and can result in tax penalties.

How to avoid it:

• Set up an organised filing system, physical and/or digital.
• Scan and store every document as soon as it is issued or received.
• Make sure documents are kept for the statutory period (normally 10 years).

4. Not consulting a certified accountant

The mistake: trying to handle tax and accounting matters without specialist support.

Consequences: Portuguese tax law is complex and constantly changing. Going without professional support can lead to non-compliance and to financial losses far greater than the cost of these services.

How to avoid it:

• Work with a certified accountant from before the business starts trading.
• Meet regularly to review performance and plan for tax.
• Treat accounting services as a strategic investment.

5. Ignoring accounting data when making decisions

The mistake: taking decisions based only on a sense of the bank balance or on past experience.

Consequences: without accounting analysis it is difficult to assess the profitability, sustainability and viability of the business and of new investments.

How to avoid it:

• Follow regular reports (income statement, plan and budget, management report, balance sheet, cash flow).
• Set financial and economic performance indicators.
• Use the accounts as the basis for strategic decisions.

Avoiding these mistakes can be the difference between a financially healthy company and one that struggles to grow or even to survive. Accounting should not be seen simply as a legal obligation but as an essential management tool. Adopting good practice early on makes for better-informed decisions, avoids penalties and boosts the chances of business success.