In accountancy, the double-entry bookkeeping (or double-entry accounting) system is the basis of the standard system used by businesses and other organizations to record financial transactions. The modern double-entry bookkeeping system was first codified by the Italian mathematician Luca Pacioli, in his Summa de arithmetica, geometrica, proportioni et proportionalità (Venice, 1494). Its premise is that a business’s (or other organization’s) financial condition and results of operations are best recorded in accounts. Each account maintains a “history” of changes in monetary values about a particular aspect of the business.
This system is called double-entry because each transaction is recorded in at least two accounts. Each transaction results in at least one account being debited and at least one account being credited, with the total debits of the transaction equal to the total credits.
For example, if Business A sells an item to Business B and Business B pays Business A by cheque, the bookkeeper of the Business A would credit the account called “Sales” and debit the account called “Bank”. Conversely, the bookkeeper of Business B would debit the account called “Purchases” and credit the account called “Bank”.
Historically, debit entries have been recorded on the left hand side and credit values on the right hand side of a general ledger account. The ledger accounts are set up as T accounts so called because they resemble the letter T when the account is empty.
The origins of a primitive double-entry system has been traced as far back as the 12th century to accounting in the Islamic world. Some sources suggest that Giovanni di Bicci de’ Medici introduced this method for the Medici bank in the 13th century. The earliest extant records that follow the modern double-entry form are those of Amatino Manucci, a Florentine merchant at the end of the 13th century. By the end of the 15th century, the merchant venturers of Venice used this system widely. Luca Pacioli, a monk and collaborator of Leonardo da Vinci, first codified the system in a mathematics textbook of 1494. Pacioli is often called the “father of accounting” because he was the first to publish a detailed description of the double-entry system, thus enabling others to study and use it.
Double-entry bookkeeping was initially introduced in Japan during the Meiji period in the 1870s. The newly-established Japan Mint was the earliest Japanese government institution to begin using double-entry bookkeeping in its Osaka headquarters.
The bookkeeping and accounting process
In the normal course of business, a document is produced each time a transaction occurs. Sales and purchases usually have invoices or receipts. Deposit slips are produced when lodgements (deposits) are made to a bank account. Cheques are written to pay money out of the account. Bookkeeping involves recording the details of all of these source documents into multi-column journals (also known as a books of first entry or daybooks). For example, all credit sales are recorded in the Sales Journal, all Cash Payments are recorded in the Cash Payments Journal. Columns in the journal normally correspond to an account. In the single entry system, each transaction is recorded only once. Most individuals who balance their cheque-book each month are using such a system, and most personal finance software follows this approach.
After a certain period, typically a month, the columns in each journal are each totalled to give a summary for the period. Using the rules of double entry, these journal summaries are then transferred to their respective accounts in the ledger, or book of accounts. The process of transferring summaries or individual transactions to the ledger is called Posting. Once the posting process is complete, accounts kept using the “T” format undergo balancing which is simply a process to arrive at the balance of the account.
To quickly check that the posting process was done correctly, a working document called an unadjusted trial balance is created. In its simplest form, this is a three column list. The first column contains the names of those accounts in the ledger which have a non-zero balance. If an account has a debit balance, the balance amount is copied into column two (the debit column). If an account has a credit balance, the amount is copied into column three (the credit column). The debit column is then totaled and then the credit column is totaled. The two totals must agree - this agreement is not by chance - it happens because under the double-entry rules, whenever there is a posting, the debits of the posting equal the credits of the posting. If the two totals do not agree therefore, an error has been made in either the journals or made during the posting process. The error(s) must be located and rectified and the totals of debit column and credit column re-calculated to check for agreement before any further processing can take place.
Once there are no errors, the accountant produces a number of adjustments and changes the balance amounts of some of the accounts. For example, the “Inventory” account and “Office Supplies” asset accounts are changed to bring them into line with the actual numbers counted during a stock take. At the same time, the expense accounts associated with usage of inventory and with the usage of office supplies are adjusted. Other refinements necessary to ensure that accounting principles are complied with are also done at this time. This results in a listing called, not surprisingly, the adjusted trial balance. It is the accounts in this list and their corresponding debit or credit balances that are used to prepare the financial statements.
Finally, financial statements are drawn from the trial balance, which may include:
- the income statement, also known as a statement of financial results, profit and loss statement, or simply P&L
- the balance sheet
- the cash flow statement
- the statement of retained earnings
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