Accounting books
Single-Entry vs Double-Entry Books: Which Suit Your Business?
Published · 9 min read · NS Accounting & Tax Office
Written by the NSTAX team of accountants and tax advisers
One of the most common questions new business owners ask is whether they need single-entry or double-entry books, and what that choice means in practice. In this article, NSTAX explains the difference, which businesses are required to use each category and when that obligation changes.
What Are Single-Entry Books?
Single-entry books (also known as category B books or an income-and-expense book) are the simplest form of accounting record. Each transaction is entered once, either as income or as an expense, without the dual entry required by the double-entry system. The tax return is derived relatively directly from this book, without the need to prepare full financial statements.
What Are Double-Entry Books?
Double-entry books (category C) are based on recording each transaction twice, showing both the source and destination of every movement. They require a full chart of accounts, trial balances and, depending on the size of the business, full financial statements (balance sheet, income statement and notes). They provide a much more detailed view of the business’s financial position, but at a higher maintenance cost.
Advantages and Disadvantages of Each System
Single-entry books — advantages
- Lower monthly accounting cost because they require less of the accountant’s time
- A simpler bookkeeping logic that is easier to understand even without specialist accounting knowledge
- Faster and more direct preparation of the tax return
Single-entry books — limitations
- A less detailed picture of the business’s financial position
- More difficult documentation for banks or investors, which often request full financial statements
- They are not permitted for capital companies, regardless of size
Double-entry books — advantages
- A complete, detailed picture of income, expenses, assets and liabilities
- Easier documentation for banks, investors or partners requesting financial statements
- A better foundation for business planning and decision-making
Double-entry books — limitations
- Significantly higher accounting support costs
- A greater administrative burden, especially when full financial statements must be prepared
- They often require more specialised accounting staff or an accounting firm
Who Is Required to Use Each Category?
Single-entry books may be used by
- Sole proprietorships and self-employed professionals with turnover below the €1,500,000 threshold
- Partnerships (OE and EE) with turnover below the same threshold
Double-entry books must be used by
- All capital companies (IKE, EPE and SA), regardless of turnover, because of their limited liability and separate legal personality
- Sole proprietorships and partnerships exceeding €1,500,000 in turnover for two consecutive financial years
The correct choice first depends on the business’s legal form.
Can I Choose Double-Entry Books Even If I Am Not Required To?
Yes. The law allows voluntary adoption of double-entry books even when the business’s turnover does not require it. Some business owners choose them when they want a more detailed picture of their financial position or when preparing for a future conversion into a capital company, such as moving from a sole proprietorship to an IKE.
An Example: When Turnover Changes the Category
Suppose a sole proprietorship using single-entry books reaches turnover of €1,600,000 in both the 2025 and 2026 financial years, exceeding the €1,500,000 threshold for two consecutive years. In that case, the business must move to double-entry books from the next accounting period, 2027, with the additional accounting obligations and bookkeeping costs this entails.
The reverse can also happen: if the turnover of a business using double-entry books remains below the threshold, it may under certain conditions move to single-entry books and reduce its accounting costs. This must be handled carefully so that important historical financial data is not lost.
4 Questions to Help You Decide
- What legal form does your business have? If it is an IKE, EPE or SA, double-entry books are mandatory regardless of turnover.
- Is your turnover approaching the €1,500,000 threshold? If so, it is wise to prepare for the transition in good time.
- Do you need a detailed financial picture for decision-making or to inform investors and banks? If so, double-entry books may be worthwhile even when they are not mandatory.
- Are you planning a future conversion into a capital company? An earlier move to double-entry books may make that transition easier.
Frequently Asked Questions
Can an IKE keep single-entry books?
What happens if I exceed the threshold for only one financial year?
Does the cost increase significantly with double-entry books?
Can I return to single-entry books if my turnover falls?
Not Sure Which Bookkeeping Category You Need?
NSTAX, an accounting and tax advisory firm in Athens, assesses your business’s legal form and turnover and guides you to the right choice, with full support through every category transition. Contact us for an initial assessment. See also NSTAX services for businesses.
Turnover thresholds and bookkeeping categories are based on the current framework (Law 4308/2014) and may be amended. Contact us for an accurate assessment of your own business.