Double Entry Accounting And Why It Matters In Business

Double-entry accounting is the foundation of modern financial accounting. It’s based on the accounting equation, where assets equal liabilities plus equity. That is the fundamental unit to build financial statements (balance sheet, income statement, and cash flow statement). The basic concept of double entry is that a single transaction, to be recorded, will hit two accounts.

Quick history of modern accounting

In a globalized world, where change happens so quickly that companies that existed for centuries – such as Lehman Brothers, founded in 1850, bankrupted in 2008 – just few things stick for centuries. 

The current accounting system is one of the few survivors. Born in 1494, when a Venetian Merchant, Luca Pacioli, in his “Summa de Arithmetica, Geometria, Proportioni et Proportionailta”, described for the first time the double entry-system. This practical manual gave official birth to a system that is still used in current accounting.  

Even people who hate accounting recognize the importance of it. If you either own a small business, or you are a CFO, CEO, COO, a common citizen, you have to understand accounting to recognize what is behind each one of the 14 trillions transactions per day, just in US. 

GAAP Principles

Although, the fundamental accounting system hasn’t changed, the principle and rules applying today have been updated in the last century. 

The general accepted accounting principles are standards and procedures used by organizations to submit their financial statements. 

Today we have two main accepted frameworks, globally: GAAP and IFRS; in this chapter I will focus mainly on GAAP. Indeed, after the 1929 market crash,

American government felt the necessity to create a set of rules to discipline and conform the accounting system, and avoid what had happened. In the decade after the 1929 market crash institutions such as the Securities and Exchange Commission were created.

In 1934, the SEC, assisted by the American Institute of Accountants (AIA), started to work on the GAAP.

The AIA subsequently instituted an organism to specifically create these principles: The Committee on Accounting Procedure (CAP). Finally, the first set of GAAP was created and in 1973 and the CAP board was substituted by the Financial Accounting Standards Board (FASB).

From this work came out 10 basic principles, that are the foundation of the modern accounting system in US:

  • Economic entity assumption: If you have a business, even if you are a sole proprietor, the accountant will consider yourself separately from your business.   
  • Monetary Unit Assumption: The Business activity you undertake is considered in US Dollars.
  • Time Period Assumption: Business activity you undertake can be reported in separated time intervals, such as weeks, months, quarters or fiscal years.
  • Cost Principle: If you buy an item in 1980 at $100, it will be reported on your balance sheet as worth $100 today, independently on inflation or appreciation of the asset.  
  • Full Disclosure Principle: You have to report all the relevant information of the business in the financial statements or in the footnotes.
  • Going Concern: The accountant assumes that your business will continue its operations in the foreseeable future. 
  • Matching Principle: If you incur an expense, it should be matched with the revenues, according to the accrual principle. If you decide to pay your employees a bonus related to 2015 but you pay it in 2016, you still will report it as 2015. You will report the expense when it was recognized and not when actual cash disbursed (accrual principle).
  • Revenue Recognition Principle: if you sell a product in January 2015 but you will receive the money from the customer in April 2015, you will report the sale in January, since it was the period when the actual sale was realizable. 
  • Materiality Principle: when you report the financials, it will be allowed to round them, since if an amount is insignificant can be neglected by your accountant. 
  • Conservatism Principle: When in doubt between $80 and $100 loss, your accountant has to choose the most conservative alternative, report $100. 

These principles are the “ten commandments” for the accountant. Keep them in mind.

They will guide you throughout the book. In addition, the accrual principle in practical terms states: “Revenues and expenses are recognized when occurred, independently from cash disbursement.”

This principle is crucial to build our main financial statements, in particular the Income Statement and Balance Sheet.

Double-entry system explained

The accounting equation is the fundamental equation that keeps together a balance sheet. Indeed, it states that assets always equal liability plus equity. The foundation of accounting is the double-entry system which assumes that a company balance sheet can be broken down in assets, and how they get sources (either though equity/capital or liability/debt).

As any other language, the accounting system has its own. Indeed, in accounting in order for you to record a transaction you have to use the double-entry system.

Double entry means that each single transaction needs to be recorded twice, on the left side if debited and on the right side if credited.

Usually, when you think of debit or credit in real life is different compared to debit or credit in accounting. In fact, debit does not mean that you have a debt to be paid back; neither credit means that you have money to receive. 

For example, in the accounting world, when cash is debited, it means the cash on your bank account increased. Therefore, you received cash. I know it may sound counterintuitive, but this system was created five hundred years ago and it is the system today’s accountants use to record each single transactions. 

T-Accounts: The Foundation

The most effective way that accountants use to record each single transaction in the ledger is the T-Account. Although, most of the accounting Software today do it automatically, it is helpful to know how it works.

This visual aid helps the accountant to record a single transaction. Each account, in fact, has two sides, debit and credit.

Therefore, for a transaction to satisfy the accounting requirements has to be recorded on both sides. We will see that in the next paragraph.

Eventually, all the transactions collected for a certain period flow in the General Ledger.

Journal Entry: The Double Faced Entry

Assuming you own a bakery that just sold $100 worth of biscuits. In the real world, it appears as a single transaction. Therefore you may think the same applies in the accounting world.

Instead, it is more complex since each single transaction implies two concurrent movements.

When you sold $100 of biscuits, your customer paid in cash. It means, on one hand, the $100 is debited to the cash account, while on the other hand, the $100 is credited to the income account. It will look like the following:

Accounts And Chart of Accounts (COA)

 By defining Accounting as the language, we can define the accounts as the letters of the alphabet. Indeed, the accounts allow to categorize the bunch of transactions happened in a certain period, under the same umbrella.

The account is a record where all the debit and credit transactions are recorded. In the previous paragraph you saw already two of the main accounts, Assets and Revenue. 

These accounts get organized under a Chart of Account (COA) or a list of items identified by an organization that will flow in the General Ledger (GL). 

This will help the company to build reports such as: Balance Sheet (BS), Income Statement (P&L) and Cash Flow Statement. 

Setting up a clear and consistent COA is crucial for the accounting department internal organization. Indeed, a disorganized COA can lead to many accounting mistakes and inaccuracies.

Below an example of best practice:

Source: Chart of Accounts by Microsoft Dynamics

 As you can see, it is suggested to use four figures. In the specific example, each account has its own range. Indeed, the assets are shown under 1xxx, liability 2xxx, equity 3xxx and so on.

It is advisable, when setting up the accounts on the chart is advisable to leave some space between the sub accounts. For example, under assets we have the sub heading “current-assets”.

Within the Current Assets, we have items such as: Cash Account, Accounts Receivable, Inventories and Prepaid Expenses. Therefore, we will have: Current Assets, 1100 code; Cash Account, 1110 code; Accounts receivable 1200 code; Inventory 1300; Pre-paid Expenses 1500, code.

Give space between the sub-accounts, this allows you to set up new sub accounts when needed. For example, if two new cash accounts are opened, you can use the coding from 1111-1199.

Therefore, you have plenty of space to organize your COA. Setting up an organized COA and making sure everyone follows it rigorously in the organization is crucial.

Indeed, according to the coded generated, all the internal reports will be built. Such as historical AR, AP, P&L, BS, GL, CFS. If the coding is wrong or disorganized so your reports will be. 

Glance at the main accounts

  • Assets: Resources owned by an organization. They will produce future benefits for the company. For example, you own a bakery that has to produce biscuits. In order for you to produce them, you have to buy a machine. The machine will be an asset for your organization. 
  • Liabilities: Obligations (Debt) contracted by an organization. Your bakery bought $100 of raw material from the supplier and you will pay in 60 days. Until the payment will be made the $100 will show as liability (future debt) on your balance sheet
  • Owner’s Equity: Amount of money or resources you endowed to your organization. The accounting definition is: Owner’s Equity = Assets – Liabilities.
  • Revenue or Income: The $ amount of sales occurred in a certain period. According to the accrual principle, income is recognized independently from cash receipt. 
  • Expenses: The $ amount of costs occurred in a certain period. According to the accrual principle, expenses are recognized independently from cash disbursement.
Financial statements help companies assess several aspects of the business, from profitability (income statement) to how assets are sourced (balance sheet), and cash inflows and outflows (cash flow statement). Financial statements are also mandatory to companies for tax purposes. They are also used by managers to assess the performance of the business.

Connected Financial Concepts

Circle of Competence

The circle of competence describes a person’s natural competence in an area that matches their skills and abilities. Beyond this imaginary circle are skills and abilities that a person is naturally less competent at. The concept was popularised by Warren Buffett, who argued that investors should only invest in companies they know and understand. However, the circle of competence applies to any topic and indeed any individual.

What is a Moat

Economic or market moats represent the long-term business defensibility. Or how long a business can retain its competitive advantage in the marketplace over the years. Warren Buffet who popularized the term “moat” referred to it as a share of mind, opposite to market share, as such it is the characteristic that all valuable brands have.

Buffet Indicator

The Buffet Indicator is a measure of the total value of all publicly-traded stocks in a country divided by that country’s GDP. It’s a measure and ratio to evaluate whether a market is undervalued or overvalued. It’s one of Warren Buffet’s favorite measures as a warning that financial markets might be overvalued and riskier.

Venture Capital

Venture capital is a form of investing skewed toward high-risk bets, that are likely to fail. Therefore venture capitalists look for higher returns. Indeed, venture capital is based on the power law, or the law for which a small number of bets will pay off big time for the larger numbers of low-return or investments that will go to zero. That is the whole premise of venture capital.

Foreign Direct Investment

Foreign direct investment occurs when an individual or business purchases an interest of 10% or more in a company that operates in a different country. According to the International Monetary Fund (IMF), this percentage implies that the investor can influence or participate in the management of an enterprise. When the interest is less than 10%, on the other hand, the IMF simply defines it as a security that is part of a stock portfolio. Foreign direct investment (FDI), therefore, involves the purchase of an interest in a company by an entity that is located in another country. 


Micro-investing is the process of investing small amounts of money regularly. The process of micro-investing involves small and sometimes irregular investments where the individual can set up recurring payments or invest a lump sum as cash becomes available.

Meme Investing

Meme stocks are securities that go viral online and attract the attention of the younger generation of retail investors. Meme investing, therefore, is a bottom-up, community-driven approach to investing that positions itself as the antonym to Wall Street investing. Also, meme investing often looks at attractive opportunities with lower liquidity that might be easier to overtake, thus enabling wide speculation, as “meme investors” often look for disproportionate short-term returns.

Retail Investing

Retail investing is the act of non-professional investors buying and selling securities for their own purposes. Retail investing has become popular with the rise of zero commissions digital platforms enabling anyone with small portfolio to trade.

Accredited Investor

Accredited investors are individuals or entities deemed sophisticated enough to purchase securities that are not bound by the laws that protect normal investors. These may encompass venture capital, angel investments, private equity funds, hedge funds, real estate investment funds, and specialty investment funds such as those related to cryptocurrency. Accredited investors, therefore, are individuals or entities permitted to invest in securities that are complex, opaque, loosely regulated, or otherwise unregistered with a financial authority.

Startup Valuation

Startup valuation describes a suite of methods used to value companies with little or no revenue. Therefore, startup valuation is the process of determining what a startup is worth. This value clarifies the company’s capacity to meet customer and investor expectations, achieve stated milestones, and use the new capital to grow.

Profit vs. Cash Flow

Profit is the total income that a company generates from its operations. This includes money from sales, investments, and other income sources. In contrast, cash flow is the money that flows in and out of a company. This distinction is critical to understand as a profitable company might be short of cash and have liquidity crises.


Double-entry accounting is the foundation of modern financial accounting. It’s based on the accounting equation, where assets equal liabilities plus equity. That is the fundamental unit to build financial statements (balance sheet, income statement, and cash flow statement). The basic concept of double-entry is that a single transaction, to be recorded, will hit two accounts.

Balance Sheet

The purpose of the balance sheet is to report how the resources to run the operations of the business were acquired. The Balance Sheet helps to assess the financial risk of a business and the simplest way to describe it is given by the accounting equation (assets = liability + equity).

Income Statement

The income statement, together with the balance sheet and the cash flow statement is among the key financial statements to understand how companies perform at fundamental level. The income statement shows the revenues and costs for a period and whether the company runs at profit or loss (also called P&L statement).

Cash Flow Statement

The cash flow statement is the third main financial statement, together with income statement and the balance sheet. It helps to assess the liquidity of an organization by showing the cash balances coming from operations, investing and financing. The cash flow statement can be prepared with two separate methods: direct or indirect.

Capital Structure

The capital structure shows how an organization financed its operations. Following the balance sheet structure, usually, assets of an organization can be built either by using equity or liability. Equity usually comprises endowment from shareholders and profit reserves. Where instead, liabilities can comprise either current (short-term debt) or non-current (long-term obligations).

Capital Expenditure

Capital expenditure or capital expense represents the money spent toward things that can be classified as fixed asset, with a longer term value. As such they will be recorded under non-current assets, on the balance sheet, and they will be amortized over the years. The reduced value on the balance sheet is expensed through the profit and loss.

Financial Statements

Financial statements help companies assess several aspects of the business, from profitability (income statement) to how assets are sourced (balance sheet), and cash inflows and outflows (cash flow statement). Financial statements are also mandatory to companies for tax purposes. They are also used by managers to assess the performance of the business.

Financial Modeling

Financial modeling involves the analysis of accounting, finance, and business data to predict future financial performance. Financial modeling is often used in valuation, which consists of estimating the value in dollar terms of a company based on several parameters. Some of the most common financial models comprise discounted cash flows, the M&A model, and the CCA model.

Business Valuation

Business valuations involve a formal analysis of the key operational aspects of a business. A business valuation is an analysis used to determine the economic value of a business or company unit. It’s important to note that valuations are one part science and one part art. Analysts use professional judgment to consider the financial performance of a business with respect to local, national, or global economic conditions. They will also consider the total value of assets and liabilities, in addition to patented or proprietary technology.

Financial Ratio



The Weighted Average Cost of Capital can also be defined as the cost of capital. That’s a rate – net of the weight of the equity and debt the company holds – that assesses how much it cost to that firm to get capital in the form of equity, debt or both. 

Financial Option

A financial option is a contract, defined as a derivative drawing its value on a set of underlying variables (perhaps the volatility of the stock underlying the option). It comprises two parties (option writer and option buyer). This contract offers the right of the option holder to purchase the underlying asset at an agreed price.

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