Debit and Credit Explained: Revenue and Expenses (Part 3)
A practical beginner-friendly explanation of how revenue and expenses work in debit and credit accounting.
Why Revenue and Expenses Matter
In Part 2, we focused on the three account types inside the basic accounting equation:
Assets = Liabilities + Equity
Now we need to understand two more account types that appear in almost every business transaction:
- Revenue
- Expenses
Revenue and expenses are the accounts that explain whether a business is making money or losing money.
Assets, liabilities, and equity tell us what the business owns, owes, and belongs to the owner.
Revenue and expenses tell us how the business performs.
Revenue increases profit. Expenses reduce profit.
Once you understand this, debit and credit become much easier because revenue and expenses are not random accounts. They connect directly to equity.
Where Revenue and Expenses Fit Into the Accounting Equation
At first, beginners often wonder why the basic accounting equation does not visibly show revenue and expenses.
The equation says:
Assets = Liabilities + Equity
So where do revenue and expenses go?
The answer is simple:
Revenue and expenses eventually affect equity.
Revenue increases the owner’s wealth because the business earned income.
Expenses reduce the owner’s wealth because the business consumed resources to operate.
That means:
- Revenue increases profit.
- Profit increases equity.
- Expenses reduce profit.
- Lower profit reduces equity.
This is why revenue behaves like equity, while expenses behave opposite to equity.
Revenue: Money Earned by the Business
Revenue is income earned from selling goods or providing services.
Revenue is not simply money received. This is important.
A business can earn revenue even before cash is received, especially when goods or services are sold on credit.
Examples of revenue include:
- Sales revenue
- Service revenue
- Consulting income
- Rental income
- Interest income
- Commission income
- Subscription revenue
Revenue means the business has earned income from its activities.
Revenue increases with credits and decreases with debits.
Why?
Because revenue increases profit, and profit increases equity.
Since equity increases with credits, revenue also increases with credits.
Example 1: Cash Sale
Your business sells goods for $800 cash.
Two things happen:
- Cash increases.
- Sales Revenue increases.
Cash is an asset. Assets increase with debits.
Sales Revenue is revenue. Revenue increases with credits.
| Debit | Credit |
|---|---|
| Cash $800 | Sales Revenue $800 |
This entry means the business received cash and earned revenue at the same time.
Example 2: Service Income Received in Cash
Your business provides a service and receives $1,200 immediately.
Two things happen:
- Cash increases.
- Service Revenue increases.
| Debit | Credit |
|---|---|
| Cash $1,200 | Service Revenue $1,200 |
The debit goes to Cash because Cash increased.
The credit goes to Service Revenue because the business earned income.
Example 3: Sale on Credit
Your business sells goods for $1,500, but the customer will pay later.
No cash is received yet.
But the business has still earned revenue.
Two things happen:
- Accounts Receivable increases.
- Sales Revenue increases.
Accounts Receivable is an asset because it represents money customers owe to the business.
Assets increase with debits.
Revenue increases with credits.
| Debit | Credit |
|---|---|
| Accounts Receivable $1,500 | Sales Revenue $1,500 |
Important lesson: Revenue is recorded when it is earned, not only when cash is received.
Expenses: Costs Incurred to Run the Business
Expenses are costs the business incurs to operate and earn revenue.
Examples of expenses include:
- Rent expense
- Salary expense
- Electricity expense
- Internet expense
- Advertising expense
- Fuel expense
- Insurance expense
- Repair expense
- Bank charges expense
Expenses reduce profit.
Lower profit reduces equity.
Since equity decreases with debits, expenses increase with debits.
Expenses increase with debits and decrease with credits.
Example 4: Paying Rent
Your business pays $1,000 for office rent.
Two things happen:
- Rent Expense increases.
- Cash decreases.
Rent Expense is an expense. Expenses increase with debits.
Cash is an asset. Assets decrease with credits.
| Debit | Credit |
|---|---|
| Rent Expense $1,000 | Cash $1,000 |
The debit records the cost of using the office space.
The credit records the reduction in cash.
Example 5: Paying Salaries
Your business pays employees $2,500.
Two things happen:
- Salary Expense increases.
- Cash decreases.
| Debit | Credit |
|---|---|
| Salary Expense $2,500 | Cash $2,500 |
The business consumed employee labor, so an expense is recorded.
The business paid cash, so cash decreases.
Example 6: Receiving a Bill But Not Paying Yet
Your business receives an electricity bill for $300 but will pay it next month.
Two things happen:
- Utilities Expense increases.
- Accounts Payable increases.
The business has already used electricity, so the expense exists.
But cash has not been paid yet.
Instead, the business owes money. That creates a liability.
| Debit | Credit |
|---|---|
| Utilities Expense $300 | Accounts Payable $300 |
Important lesson: Expenses can be recorded before cash is paid.
Revenue and Expenses Are Not the Same as Cash In and Cash Out
This is one of the most important lessons for non-accountants.
Many people think:
- Money received = revenue
- Money paid = expense
That is sometimes true, but not always.
Accounting looks at what the business earned and incurred, not only what cash moved.
| Situation | Accounting Meaning |
|---|---|
| Customer pays immediately after service | Cash increases and revenue is earned |
| Customer will pay later | Accounts Receivable increases and revenue is earned |
| Business pays rent immediately | Expense increases and cash decreases |
| Business receives bill but pays later | Expense increases and liability increases |
This is why accounting gives a more complete picture than simply looking at the bank balance.
The Five Account Types Together
Now we can combine everything into one complete beginner framework.
| Account Type | Examples | Increases With | Decreases With |
|---|---|---|---|
| Assets | Cash, inventory, equipment, receivables | Debit | Credit |
| Expenses | Rent, salaries, utilities, advertising | Debit | Credit |
| Liabilities | Loans, payables, taxes payable | Credit | Debit |
| Equity | Owner capital, retained earnings | Credit | Debit |
| Revenue | Sales, service income, fees earned | Credit | Debit |
Assets and Expenses increase with debits. Liabilities, Equity, and Revenue increase with credits.
The Part 3 Takeaway
Revenue and expenses complete the beginner framework of debit and credit.
You now know that revenue increases profit and therefore increases equity. That is why revenue increases with credits.
You also know that expenses reduce profit and therefore reduce equity. That is why expenses increase with debits.
If you remember only one thing from Part 3, remember this:
Revenue makes equity stronger. Expenses make equity weaker.
In Part 4, we will move from explanation to repetition by looking at more than 30 real-world transactions. That is where debit and credit begins to become natural.