What Is Double-Entry Bookkeeping? Debits, Credits, the DEAD Rule and a Worked Example

CFI puts it this way: for every entry into an account, there must be a corresponding and opposite entry into a different account. Its main purpose is to keep a company's accounts balanced, so they give an accurate picture of its financial position to management and to outsiders such as investors, shareholders, suppliers and the government.

The accounting equation behind every entry

Double entry rests on one equation: Assets = Liabilities + Shareholders' Equity. CFI explains that a debit in one account must be matched by a credit in another, so the equation holds after every transaction. Debits usually sit on the left side of a ledger and credits on the right.

Accountants often sketch this with T-accounts, a simple T shape with debits on the left and credits on the right, which CFI says gives a visual picture of figures moving between accounts. In your actual books, those entries land in the general ledger, account by account.

A worked double-entry example

CFI's example is Alpha Company, which buys $5,000 of furniture for its office and pays cash (CFI's US-dollar example, as of October 2026). Two accounts move: the furniture account goes up, and the cash account goes down.

Account	Debit	Credit
Furniture (an asset)	$5,000
Cash (an asset)		$5,000
Total	$5,000	$5,000

Furniture is debited, cash is credited, and the debit equals the credit at $5,000. Total assets haven't changed at all, because one asset was swapped for another. The equation still balances, which is exactly what the system is designed to prove.

The catch: debit doesn't mean increase

This is where most people get stuck. CFI is clear that a debit or a credit doesn't mean increase and decrease. Whether a debit pushes an account up or down depends on the type of account. CFI's simple method: a debit is needed to increase an asset account, while a credit is needed to increase a liability account.

CFI's memory aid is the DEAD rule: always Debit Expenses, Assets and Dividends. Those accounts normally carry a debit balance, so debits increase them and credits decrease them. Every other account works the exact opposite way. Here's a summary of CFI's rules:

Account (summary of CFI's rules)	A debit	A credit
Asset (for example, furniture)	Increases it	Decreases it
Asset (cash)	Increases it	Decreases it
Liability	Decreases it	Increases it
Expense	Increases it (DEAD)	Decreases it

So in the Alpha Company example, the credit to cash is a decrease, because cash is an asset. If the furniture had been bought on credit instead, the credit would have gone to a liability, and that credit would have been an increase.

The five account types double entry works with

CFI lists five common types of account:

• Asset: goods, equipment and cash the business owns.
• Liability: what it owes to others, such as goods bought on credit, a mortgage or credit card balances.
• Capital: shareholders' equity, such as common stock, preferred stock and retained earnings.
• Expense: costs such as advertising, payroll, administrative costs and rent.
• Income: interest or investment income, and revenue from selling goods or services.

How to record a transaction with double entry

1. Identify the two accounts the transaction touches.
2. Decide which side of each account moves, debit or credit, using the DEAD rule.
3. Record equal debit and credit amounts.
4. Check that Assets = Liabilities + Equity still holds.
5. If it doesn't, trace the imbalance back to the entry before you go any further.

Why double entry catches mistakes early

CFI says the chance of administrative errors goes up as a company grows and its transactions get more complex. Double entry doesn't wipe out every error, but it limits errors in the balance sheet and other statements, because the debits and credits have to balance. When they don't, you can trace the wrong entry before it turns into a bigger, tangled problem.

Balancing isn't the same as being right, though. A transaction that was never entered at all leaves both sides equal. I've listed the errors that can still slip through in my guide to the trial balance, which is the report that checks your debits and credits add up.

Where double-entry bookkeeping came from

It's older than you'd think. CFI says double entry has been in use for at least hundreds, if not thousands, of years, with simplified versions in Roman and early Medieval Middle Eastern civilisations. The modern system is credited to Italian merchants, who used it widely in the 13th and 14th centuries. The first documented record dates to 1494, when Luca Pacioli, often called the Father of Accounting, published a book setting out the method.

My verdict on double entry

Every transaction has two sides, and if the two sides don't match, you've found an error before it grows. That's the whole beauty of it. You don't need to love debits and credits; you just need to remember that debit doesn't mean up, learn the DEAD rule, and check that each entry balances. If you'd like a few more habits that make the books less painful, these easy bookkeeping tips are a good next read.

Frequently asked questions

What is the DEAD rule in accounting?

CFI's DEAD rule says always Debit Expenses, Assets and Dividends. Those accounts normally carry a debit balance, so debits increase them and credits decrease them. Other accounts work the opposite way.

Does a debit mean an increase?

No. CFI says a debit or credit doesn't mean increase or decrease. A debit increases an asset account, while a credit increases a liability account.

What is an example of double-entry bookkeeping?

In CFI's example, Alpha Company buys $5,000 of furniture for cash. Furniture is debited $5,000 and cash is credited $5,000, so the two sides match.

Who invented double-entry bookkeeping?

The modern system is credited to Italian merchants in the 13th and 14th centuries. CFI says the first documented record dates to 1494, when Luca Pacioli published a book detailing the method.

Does double entry stop all errors?

No. CFI says it limits errors because debits and credits must balance, which lets incorrect entries be traced early, but it doesn't eliminate every mistake.